SEISMIC RISK ASSESSMENT OF VA HOSPITAL BUILDINGS
Risk Assessment Methods
Phase I Report
Prepared for:
Office of Facilities Management
Department of Veterans Affairs
Washington, D.C.
Prepared by:
National Institute of Building Sciences
Washington, D.C.
Subcontractors:
Kircher and Associates
Palo Alto, California
Degenkolb Engineers
San Francisco, California
April 13, 2010
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report - Approach and Methods
April 13, 2010
EXECUTIVE SUMMARY
The Department of Veteran Affairs (VA) intends to assess earthquake risk and rank 52 VA
hospital buildings located in areas of high and very high seismicity using a HAZUS-based
technology developed for this purpose by Kircher and Associates and Degenkolb Engineers
under contract to the National Institute of Building Sciences (NIBS). This technology represents
the state of the art for seismic risk assessment, and represents a new tool that will be valuable to
the VA in their future efforts related to the mitigation of seismic hazards in the VA building
inventory.
The seismic risk assessment technology evaluates collapse risk using HAZUS-based methods
similar to the on-going and successful OSHPD (SB 1953) program to re-prioritize California
hospital buildings. Additionally, the technology addresses a broader range of VA program goals
by calculating damage to nonstructural components and contents, as well as the structural
system, and by estimating expected losses that include casualties (deaths and injuries), loss of
function (downtime) and dollar losses (costs to repair or replace damaged systems).
The technology can be used to evaluate the seismic risk of a single building, a number of
buildings at a specific medical center, a larger number of buildings in an entire region, and an
even larger number of buildings within an entire region (VISN). The technology includes a "risk
point" ranking scheme for comparing relative risks of casualties, dollar losses and loss of
function, respectively, and for ranking a portfolio of buildings in terms of total seismic risk. This
combined risk approach is similar, in many ways, to the EHR ranking system developed as part
of the VA Seismic Program.
The HAZUS technology developed for the VA presents a state-of the-art tool that provides a
consistent, technically defendable and comprehensive approach to seismic risk assessment. The
technology can be used to perform a wide variety of risk assessments of great benefit to the VA
for planning of future expenditures, post-earthquake response, and various other items. The 52
buildings selected for this study comprise a number of different building types, occupancies,
seismic exposures and structural and nonstructural seismic vulnerabilities. This broad selection
of buildings permits exercising and validating the technology as a useful tool for future VA
studies.
This report documents Phase I development of HAZUS-based methods that are used during
Phase II for seismic risk assessment of the selected (52) VA buildings. The HAZUS-based
methods are of a highly technical and complex nature, and are implemented in an Excel
spreadsheet, referred to as the Risk Calculation Tool (RCT). Main body of the Phase I report
(Chapters 2 through 7) are intended primarily for use by engineers developing the RCT or
performing risk assessments, and by the NIBS Oversight Committee for review of underlying
concepts, methods and data of the technology.
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April 13, 2010
TABLE OF CONTENTS
Executive Summary ..................................................................................................................... ii
Chapters
Page
1.
Introduction ..................................................................................................................
1.1
Background ......................................................................................................
1.2
VA Program Goals ...........................................................................................
1.3
Project Organization .........................................................................................
1.4
Scope of Work ..................................................................................................
1.5
Project Approach ..............................................................................................
1.5.1 Risk Assessment and Data Sources ......................................................
1.5.2 Risk Results ..........................................................................................
1.5.3 Risk Calculation Tool ..........................................................................
1.6
Report Content ..................................................................................................
2.
Building Data ................................................................................................................ 2-1
2.1
Introduction ...................................................................................................... 2-1
2.2
Building Parameters and Sources .................................................................... 2-2
2.2.1 Occupancy Class ................................................................................. 2-4
2.2.2 Number of Occupants and Beds .......................................................... 2-4
2.2.3 Replacement Costs ............................................................................... 2-4
2.2.4 Seismic Design Level and Design Coefficient (Cs) ............................. 2-8
2.2.5 Seismic Performance Rating ............................................................... 2-9
2.2.6 Data Quality Rating ............................................................................. 2-10
2.3
Structural Deficiencies .................................................................................... 2-11
2.4
Nonstructural Deficiencies ............................................................................. 2-15
3.
Ground Motion Data ....................................................................................................
3.1
Introduction .......................................................................................................
3.2
Code Ground Motions ......................................................................................
3.3
Probabilistic Ground Motions ..........................................................................
3-1
3-1
3-2
3-8
4.
Capacity and Response Parameters ..............................................................................
4.1
Response Calculation ........................................................................................
4.2
Values of Capacity Parameters ........................................................................
4.3
Values of Response Parameters .......................................................................
4-1
4-1
4-3
4-9
5.
Damage (Fragility) Parameters ..................................................................................... 5-1
5.1
Damage-State Probability ................................................................................. 5-1
5.2
Values of Structural Fragility Parameters ......................................................... 5-4
5.3
Values of Nonstructural Fragility Parameters ................................................. 5-11
5.3.1 Nonstructural Drift-Sensitive (NSD) Components ............................. 5-11
5.3.2 Modification of Spectral Acceleration
NSA Components and Contents ......................................................... 5-11
5.3.3 Nonstructural Acceleration-Sensitive (NSA) Components ................ 5-12
iii
1-1
1-1
1-2
1-2
1-3
1-5
1-5
1-6
1-7
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6.
Loss Parameters ........................................................................................................... 6-1
6.1
Loss Calculation ............................................................................................... 6-1
6.1.1 Expected Value of Loss ........................................................................ 6-1
6.1.2 Average Annualized Loss ..................................................................... 6-2
6.2
Casualty Loss Parameters ................................................................................ 6-4
6.3
Economic Loss Parameters ............................................................................... 6-7
6.4
Functional Loss Parameters .............................................................................. 6-10
6.4.1 Expected Loss of Function due to Structural Damage ....................... 6-10
6.4.2 Expected Loss of Function due to Nonstructural Damage ................. 6-11
6.4.3 Probability of Loss of Function .......................................................... 6-15
7.
Risk Calculation Tool ................................................................................................... 7-1
7.1
Introduction ...................................................................................................... 7-1
7.2
Features and Use .............................................................................................. 7-2
7.2.1 Getting Started ..................................................................................... 7-2
7.2.2 User Operation ...................................................................................... 7-2
7.2.3 Input Data ............................................................................................. 7-7
7.2.4 Output Data .......................................................................................... 7-7
7.3
Example Evaluation of Two VA Buildings .................................................... 7-8
7.4
Risk Point Ranking Scheme ............................................................................. 7-17
7.5
Example Risk Point Ranking of 52 VA Buildings ......................................... 7-19
8.
Conclusion ....................................................................................................................
8.1
Summary ...........................................................................................................
8.2
Limitations on Application ...............................................................................
8.3
Future Studies and Improvements ....................................................................
9.
References ..................................................................................................................... 9-1
10.
Glossary ....................................................................................................................... 10-1
8-1
8-1
8-2
8-4
Appendices
A.
OSHPD (SB 1953) "HAZUS" Regulations ................................................................ A-1
B.
Example Building Seismic Evaluation - Roseburg, Building 1 .................................. B-1
C.
Example Building Seismic Evaluation - Prescott, Building 107 ................................. C-1
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CHAPTER 1. INTRODUCTION
1.1
Background
In late 2007, California’s Office of Statewide Health Planning and Development (OSHPD)
began using the earthquake damage and loss estimation methods of HAZUS-MH (Hazards U.S.
Multi-Hazard) 1 as one of the tools in the SB (Senate Bill) 1953 program mandated by the state
in the wake of damage to hospital facilities in the 1994 Northridge earthquake. This program
incorporates HAZUS-based methods in regulations ((OSHPD, 2007) for re-prioritization
screening of a large number of buildings previously identified as potential collapse risks (i.e.,
SPC-1 buildings). These regulations allow reclassification of SPC-1 buildings) based on a
collapse probability assessment, consistent with seismic safety requirements of SB 1953.
SPC-1 buildings shown to have a very low probability of collapse for strong ground motions of
not more than three-quarters of one percent (0.75%) may be reclassified as SPC-2 buildings,
effectively postponing the date that California State law requires either seismic retrofit or a
change in use of these buildings. The objective of the OSHPD re-reprioritization effort is to
address the "worst first," recognizing that it is not feasible or practical to address all SPC-1
buildings in the time frame mandated by SB 1953. The acceptable probability of collapse,
0.75%, effectively allows owners of about two-thirds of the hospital buildings initially classified
as SPC-1 to defer seismic action until 2020.
The OSHPD regulations consider only collapse performance in the re-prioritization of SPC-1
buildings. Other performance objectives important to hospital buildings, including postearthquake functionality, are addressed by long-term goals of SB 1953, and SPC-1 buildings reclassified as SPC-2 buildings are still required to be seismically retrofitted to meet all applicable
performance objectives (i.e., seismic performance comparable to that of a new hospital building),
or be removed from hospital service by 2030.
The Department of Veteran Affairs (VA) now intends to evaluate VA hospital buildings located
in areas of high and very high seismicity based on the success achieved using the HAZUS-MH
methodology in the SB 1953 program. VA hospital building evaluations follow the same
approach, and are generally consistent with, the re-prioritization methods of the OSHPD
regulations, but are significantly enhanced to address a broader range of VA program goals and
related performance objectives. This report documents the approach and HAZUS-based methods
for seismic assessment of selected VA hospital buildings.
1
HAZUS-MH is a methodology and software program that estimates potential losses from earthquakes, hurricane
winds, and floods nationwide. It was developed by the National Institute of Building Sciences under agreements
with the Federal Emergency Management Agency (FEMA).
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The HAZUS-based methods developed for the VA is a state-of the-art technology that provides a
consistent, technically defendable and comprehensive approach to seismic risk assessment. The
technology is a powerful tool for performing a wide variety of assessments that can be of great
benefit to the VA for planning of future expenditures, post-earthquake response, and various
other items.
1.2
VA Program Goals
The VA has established both primary and secondary goals for the seismic assessment project.
Program goals of primary importance to the VA include the following:
•
Determine collapse probability as an indicator of life safety or casualties in VA facilities
(i.e., same life-safety performance measure as that used by OSHPD for re-prioritization
of SPC-1 buildings).
•
Determine the probability of structural and nonstructural damage as an indicator of the
potential level of post-earthquake facility operation. Theoretically, this should entail
continuous operation of all systems required for continued occupancy of the building
(e.g., emergency power and operating rooms).
Program goals of lesser importance to the VA include the following:
•
Support the VA’s response following an earthquake. Develop data that can be used to
help decide which buildings should be instrumented to measure seismic forces on the
building and provide data for determining at what point facilities should be vacated.
•
Support the VA’s decisions on seismic retrofit. Develop data that can be used to evaluate
facility performance before and after proposed seismic retrofits (i.e., define potential
benefits of risk reduction). This goal necessarily requires methods that more broadly
address life safety risk (deaths and injuries), loss of function (downtime) and economic
losses (costs to repair or replace damaged systems and contents) and a much more
comprehensive building data, including replacement costs, number of occupants, etc.
The VA intends to use the analysis of life safety risk and structural/nonstructural damage to
prioritize facilities for retrofit to, first, prevent collapse and, second, to sustain, at the most, only
moderate facility damage to ensure post earthquake operational capability. The cost of
retrofitting will not be a factor in ranking buildings (that is benefit-cost analysis is not part of the
scope of work).
1.3
Project Organization
To support the seismic evaluation effort, the VA has contracted with the National Institute of
Building Sciences (the Institute) to conduct a 12-month two-phase project. Phase 1 is an eightmonth effort that involves the development of the evaluation approach and methods and Phase 2
is a seven-month effort beginning at the end of month five that will provide for execution of the
evaluations of selected buildings. Each project phase will involve:
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•
Two subcontractors – Charles Kircher, Charles Kircher & Associates, and James Malley,
Degenkolb Engineers – engaged by the Institute to assist in the project.
•
An Oversight Committee consisting of William Holmes of Rutherford and Chekene, John
Gillengerten of John D. Gillengerten, Consulting Structural Engineer, and William Graf
of URS to monitor subcontractor efforts and evaluate the project deliverables.
•
Project management provided by the Institute’s Philip Schneider.
Scope of Work
The overall scope of work includes seismic evaluation of the 52 VA hospital buildings, as
summarized in Table 1-1. Table 1-1 shows that these buildings are located at 28 different VA
facility sites, geographically distributed among 12 regions (VA VISNs) around the United States.
The 52 buildings have a number of different structural systems and uses, including acute care,
long-term care and administrative occupancies. Thus, seismic methods must accommodate a
variety of hospital buildings and seismic hazard environments.
Table 1-1. Summary of 52 buildings at 28 medical center facilities located in 12 VISNs of
VA Seismic Assessment Project (consistent with H-18-08, DVA, 2008)
Vision (VA Region)
VA Medical Center
ID No. of
VISN
United States
Region
No. of
Facilites
1
New England
2
3
NY/NJ Integrated
3
7
8
Southeast
Sunshine
1
1
15
16
Heartland
South Central
1
1
18
Southwest
2
19
Rocky Mountain
1
20
Northwest
7
21
Sierra Pacific
4
22
Desert Pacific
4
Seismicity
ID No.
ML
ML
MH
ML
MH
MH
H
ML
H
MH
MH
ML
MH
VH
H
VH
VH
MH
MH
H
VH
VH
VH
VH
VH
VH
VH
VH
405
523
561
620
630
544
672
626
657A5
598A0
501
649
436
463
648
653
663
687
692
663A4
612
640
654
662
600
664
691A4
691
1-3
Facility Name
(City, State)
White River Junction, VT
Boston, MA
East Orange, NJ
Montrose, NY
New York, NY
Columbia SC
San Juan, PR
Nashville, TN
Marion, IL
North Little Rock, AR
Albuquerque, NM
Prescott, AZ
Fort Harrison, MT
Anchorage, AK
Portland, OR
Roseburg, OR
Seattle, WA
Walla Walla WA
White City, OR
American Lake, WA
Martinez/NCSC, CA
Palo Alto, CA
Reno, NV
San Francisco, CA
Long Beach, CA
San Diego, CA
Sepulveda, CA
West Los Angeles, CA
No. of
Bldgs.
1
2
2
2
1
2
1
1
2
2
2
2
2
1
2
2
2
2
2
2
1
2
2
3
2
2
2
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Seismic Risk Assessment of VA Hospital Buildings
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April 13, 2010
The VA Project includes two phases of work: Phase 1 development of the evaluation approach
and methods and Phase 2 implementation of these methods in the evaluation of the 52 buildings
of Table 1-1. Phase 1 work, the subject of this report, includes the following tasks:
Preliminary Work
•
•
Assemble background information
Meet with VA - Establish Program Goals
Main Technical Work
•
Develop Risk Assessment Methods:
o
Define earthquake ground motions used in seismic risk assessments
o
Identify building data (from existing building evaluation reports)
o
Develop HAZUS-compatible methods
o
Implement methods in Risk Calculation Tool (RCT)
o
Perform trial runs and verify RCT
The scope of work includes development of HAZUS-compatible methods, in particular,
developing and relating appropriate values of HAZUS parameters to information
obtained from existing seismic evaluation reports and the implementation of trial values
of these parameters in an Excel spreadsheet (RCT).
Project Management and Oversight
•
Meet with VA and Oversight Committee
The scope of work includes project meetings (either in Washington or by teleconference)
with VA personnel and Oversight Committee at 50%, 75% and 90% stages of
development of assessment methods.
Report Preparation
•
Prepare report documenting Phase I work
The scope of work includes draft report material to be prepared and distributed for review
and comment by VA and Oversight Committee at 50%, 75% and 90% stages of
development of assessment methods.
The following items are not in the scope of work for this project:
•
•
•
•
•
Obtaining additional facility data (not in existing seismic evaluation reports).
An analysis of risk due to ground failure (i.e., liquefaction).
An analysis of risk sharing among facilities (e.g., moving patients to less damaged
facilities).
Systems (network) analysis of building components for operability.
Consideration of the impacts of component failure (e.g., boiler plant shut-down) on
facility function.
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Project Approach - Phase I
The approach of the project for Phase I work may be summarized by the three elements, listed
below and described in subsequent sections:
(1)
Adapt damage and loss methods of the HAZUS AEBM and OSHPD (SB 1953)
regulations for VA risk assessments; incorporating the most current seismic hazard data
available from the USGS.
(2)
Tailor methods to generate risk results that address the specific goals and objectives of
the VA with respective to hospital seismic performance.
(3)
Implement methods in an Excel spreadsheet, referred to as the Risk Calculation Tool
(RCT) that serves as both a development tool during Phase I and an implementation tool
during Phase II work.
1.5.1
Risk Assessment Methods and Data Sources
The risk assessment methods developed for VA hospital building are based on and incorporate
existing seismic evaluation report data, United States Geological Survey (USGS) seismic hazard
data, HAZUS AEBM methods and OSHPD (SB 1953) methods, respectively, as summarized
below.
Seismic Evaluation Reports. VA risk assessment methods maximize the use of building
information available from existing seismic evaluation reports (Degenkolb studies), recognizing
that some reports may have very complete and reliable data while others may have data of lesser
quality due to the depth of the study (Preliminary vs. Detailed in terms of VA Seismic Program).
Methods specifically account for the quality of data, incorporating additional uncertainty in the
calculation of results for those buildings that have lesser quality data.
USGS Seismic Hazard Data. VA risk assessment methods incorporate the most up-to-date
seismic hazard data available from the United States Geological Survey (USGS). The new
ground motion hazard functions developed by the USGS for the National Seismic Hazard
Mapping Project will be used for probabilistic ground motions (USGS, Open File Report 20081128). The new seismic design values developed by the USGS as part of Project 07 for use in
the 2009 NEHRP Recommended Provisions (FEMA, 2009) and ASCE 7-10 (ASCE, 2010) will
be used for design basis ground motions (i.e., design earthquake and maximum considered
earthquake ground motions, respectively).
HAZUS Methods. In general, VA risk assessment methods are based HAZUS methods (i.e.,
approach similar to that of the HAZUS AEBM) for calculating structural damage-state
probabilities and mean estimates of building losses such as casualties, downtime and economic
losses. There are, however, some distinct differences. For example, VA methods account for the
quality of data, and structural and nonstructural deficiencies identified by seismic evaluation of
the building, and incorporate other embellishments of HAZUS methods and parameters, as
described in this report.
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OSHPD (SB 1953) Methods. In general, VA risk assessment methods calculate the probability
of collapse considering significant structural deficiencies identified by seismic evaluation of the
building in the same manner as the OSHPD (SB 1953) reprioritization work. There are,
however, distinct differences. Ground motions used for evaluation of VA hospital buildings are
not the same as those of the OSHPD (SB 1953) program, and the acceptable probability of
collapse (0.75%) of the OSHPD (SB 1953) program does not apply to VA hospital buildings.
1.5.2
Project Approach - Risk Results
The results of assessments of VA buildings include a variety of risk parameters to meet primary
and secondary program objectives, as summarized below:
Primary Program Objectives:
1. Probability of Collapse. The probability of collapse is based on the probability of Complete
structural damage (i.e., a fraction thereof) and incorporates the effects of significant
structural deficiencies.
2. Probability of Structural Damage. The probability of Slight, Moderate, Extensive and
Complete structural damage is based on building-specific properties and incorporates the
effects of significant structural deficiencies, if any.
2. Probability of Nonstructural System and Contents Damage. The probability of Slight,
Moderate, Extensive and Complete damage to nonstructural systems and contents is based on
building-specific properties and incorporates the effects of significant nonstructural
deficiencies, if any.
Secondary Program Objectives (Benefits of Risk Reduction due to Seismic Retrofit)
1. Casualties (deaths). The expected number of deaths and serious injuries is based on
probabilities of structural damage and collapse, and building-specific properties (including
the number of occupants), and incorporates the effects of significant structural deficiencies, if
any. In contrast to the probability of collapse (primary objective Item 1, above), expected
casualties considers the number of occupants in the buildings (i.e., high population buildings
pose a greater life-safety risk than low population buildings, all else equal).
2. Loss of Function (downtime). The expected number of days that the building will be
temporarily closed (i.e., temporary loss of function) is based on probabilities of structural and
nonstructural damage, and building-specific properties (including use-dependent repair and
recovery times), and incorporates the effects of significant structural deficiencies, if any. In
contrast to damage state probabilities (primary objectives, Items 2 and 3, above), expected
loss of function quantifies the likely number of days the building would be temporarily
closed for repairs.
3. Economic Loss (dollars). The expected costs of repair or replacement of damage to the
structural system, nonstructural systems and contents, respectively, is based on probabilities
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of damage to these systems and contents, and building-specific properties (including value of
the building), and incorporates the effects of significant structural deficiencies, if any. Like
expected casualties, expected costs of repair reflect building value (i.e., larger, more valuable
buildings pose a greater economic risk than smaller, less valuable buildings, all else equal).
4. Average Annualized Loss (AAL). The above measures of risk (deaths, dollars and
downtime) are calculated for specific levels of ground motions (e.g., design earthquake or
maximum considered earthquake ground motions) and, thus, are conditional on those specific
levels of ground motions occurring. As alternative measures of these risk parameters,
respectively, casualties, downtime and economic loss are also calculated in terms of their
average values on an annualized basis, referred to as average annualized loss (AAL). AAL is
based on hazard function data of the facility site, effectively combining losses from all levels
of ground motions, and provides a more equitable basis of comparing the relative risk to
buildings at sites that have significantly different hazard levels.
1.5.3
Project Approach - Risk Calculation Tool
VA building risk results are calculated using the Risk Calculation Tool (i.e., an Excel
spreadsheet programmed with VA risk assessment methods and data). Ultimately, the Risk
Calculation Tool will be used to generate risk results for Phase II evaluation and comparison of
the 52 VA hospital buildings listed in Table 1-1.
For Phase I work, the RCT provides a convenient means of performing trial assessments of the
draft assessment methods and data. Trial building assessments of various model building types,
heights and design vintages are made to test draft methods and data and develop improvements
thereto. Results are evaluated in light of the following two criteria
(1)
Relative Risk Criteria - Do trends in risk parameters (e.g., probability of collapse) of
different model building types make sense (e.g., are unreinforced masonry buildings
more risky than reinforced masonry buildings of the same height, age, etc.)?
(2)
Absolute Risk Criteria - Do values of risk parameters make sense when compared with
observed earthquake damage and loss, and estimates from related programs (e.g.,
collapse probability should be the same as that of the OSHPD program for the same
building properties and ground motions)?
The RCT permits several options with respect to building evaluation. For example, all buildings
in the portfolio (e.g., all 52 buildings) can be evaluated at the same time (e.g., to compare risk for
different buildings in the portfolio), or an individual building can be evaluated (e.g., to assess
benefits of seismic rehabilitation). Similarly, the RCT also allows use of different sets of ground
motions for risk assessment (e.g., design basis or probabilistic ground motions).
The RCT also users to input "hypothetical" parameter values for a building (e.g., to test the
sensitivity of risk results to changes in various building parameters, or to evaluate potential
benefits of rehabilitation by assuming that certain, or all, significant deficiencies are mitigated,
etc.).
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Report Content
Chapter 2 describes the types of general building data required for seismic risk evaluations,
including occupancy class (building use), number of occupants (and number of beds for acute
and long-term care buildings), replacement costs, seismic design level and design coefficient,
seismic performance rating, data quality rating, structural and nonstructural deficiencies. Each
building parameters is described and source(s) of the data identified. The primary source of
these data is the building's seismic evaluation report (i.e., Degenkolb study). Certain data,
including the number of occupants (and number of beds) and replacement costs, typically are not
available, and tables in Chapter 2 provide default values of these data as a function of building
square footage.
Chapter 3 describes the ground motion data used for seismic risk evaluations, Code and
Probabilistic ground motions, respectively. Code ground motions include the Design and MCE
ground motions of ASCE 7-05 and ASCE 7-10 for each of the 28 facility sites. Code ground
motions of ASCE 7-10 are used for risk evaluations: ASCE 7-05 ground motions are provided
for comparison. Probabilistic ground motions represent ten discrete levels of seismic hazard,
with return periods ranging from 10 years to approximately 10,000 years. All ground motions
represent the most current seismic hazard information available from the United States Seismic
Hazard Mapping Program (USGS). Chapter 3 also includes site class for each of the 28
facilities. These data are typically provided as part of the seismic evaluation reports. A default
value of Site Class D is assumed when the actual is not known.
Chapters 4, 5 and 6 describe "HAZUS" parameters related to building capacity and response,
damage (fragility), and loss, respectively, required for risk evaluation. These chapters each
begin with a discussion of the subject process (e.g., calculation of peak building response) and
then systematically define the various parameters required by the subject process. Tables in
these chapters provide values of each parameter, which are typically a function of general
building data (Chapter 2). For example, the elastic period of the building, a capacity curve
parameter, is a function of three general building data, the type of structural system also known
as model building type (MBT), the number of stories and the Seismic Design Level (SDL). Like
Chapter 3, Chapters 4, 5, and 6, are of highly technical nature and serve primarily to document
the theory and data underlying the methods used for seismic risk evaluation.
Chapter 7 describes the features, use and verification of the Risk Calculation Tool (RCT).
Features of the RCT include a "risk point" ranking scheme that assigns risk points to casualties,
dollar losses and function-related damage, respectively, for comparison of seismic risk of
different buildings. Chapter 7 includes example seismic risk evaluations of two (of the 52) VA
buildings, Roseburg 1 and Prescott 107, and an example risk point ranking of the 52 VA
buildings.
Chapter 8 provides a summary of the seismic risk assessment technology developed for the
Department of Veteran Affairs (VA), discusses limitations on applications of the technology, and
suggests additional studies to improve certain data or methods of the technology.
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Chapter 9 is a list references and sources of information and Chapter 10 is a glossary of terms
(and acronyms) used in the Phase I report.
Appendices provide copies of supporting material, including the OSHPD (SB 1953) "HAZUS"
regulations (Appendix A), the building seismic evaluation report, Roseburg 1 (Appendix B) and
the building seismic evaluation report, Prescott 107 (Appendix C).
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CHAPTER 2. BUILDING DATA
2.1
Introduction
This chapter describes building data obtained directly, or derived from existing seismic
evaluation reports. These data are specific to each building and define the values of various
parameters that are used with site-specific ground motion data (Chapter 3) to assess seismic risk
for each VA building.
Most building data are based on seismic evaluation reports prepared between 1999 and 2005 by
Degenkolb Engineers for the 52 VA buildings listed in Table 1-1. These reports evaluate
buildings in accordance with the methods of ASCE 31, Seismic Evaluation of Existing Buildings
(ASCE, 2003) or the predecessor document, Handbook for the Seismic Evaluation of Buildings A Prestandard, FEMA 310 (FEMA, 2000). The methods and criteria of these documents are
derived from the NEHRP Handbook for Seismic Evaluation of Existing Buildings, FEMA 178
(FEMA, 1992) which was the basis for building evaluations required by OSHPD (SB 1953)
regulations (OSHPD, 2007). As such, seismic evaluation methods are similar. However, ASCE
31 checklists used by Degenkolb to document VA building deficiencies are somewhat different
in format from those of the OSHPD (SB 1953) regulations (included as Appendix A).
The scope of the seismic evaluation reports is not the same for all buildings. Some reports
include only limited (Tier 1) evaluation of the building (designated as “Preliminary” in the VA
Seismic Program), while others are based on a more comprehensive (Tier 2) evaluation
(designated as “Detailed” in the VA Seismic Program). Fortunately, a Tier 2 evaluation was
made for most of the 52 VA buildings in the scope (Table 1-1). Appendices B and C contain two
examples of typical (Tier 2) seismic evaluation reports, "Department of Veterans Affairs Seismic
Inventory Phase 3, Roseburg, Building 1" (Degenkolb, 2001) and "Department of Veterans
Affairs Seismic Inventory Phase 6, Prescott, Building 107"(Degenkolb, 2005), respectively. As
shown therein, these reports provide a detailed description of the building (with drawings and
photographs) and analyses performed, and include evaluation summary sheets and pertinent
checklists.
Each evaluation report includes a "VA Summary Sheet" which provides basic building data (e.g.,
building name, location, type, use, etc.) and summarizes findings, and an "ASCE 31 Summary
Data Sheet" which provides additional building data (e.g., latitude and longitude of site, year
built, area, height), construction data (i.e., on structural and foundation systems), lateral-force
resisting system data, seismic evaluation data and building classification. In addition to the
VA/ASCE 31 Summary Sheets, as many as six ASCE 31 checklists are attached to seismic
evaluation reports. The ASCE 31 checklists identify structural and nonstructural deficiencies
that are used in the seismic risk assessments of this study to adjust various HAZUS parameters,
in a manner similar to the OSHPD (SB 1953) regulations.
Table 3-2 of ASCE 31 specifies the number and type of checklists required for Tier 1 (and Tier
2) building evaluation as a function of the level of seismicity (Low, Moderate or High) and the
level of performance (Life Safety or Immediate Occupancy). These checklists include: (1) basic
2-1
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
structural checklist, (2) supplementary structural checklist, (3) geologic site hazards and
foundation checklist (not used to identify structural deficiencies for VA risk assessment), (4)
basic nonstructural checklist, (5) intermediate nonstructural checklist, and (6) supplemental
nonstructural checklist (not included with the example report). Different versions of the
structural checklists are tailored to include only those items pertinent to the model building type
of interest (e.g., model building type, S5, steel frames with infill masonry shear walls and rigid
or stiff diaphragms, in the example evaluation report included as Appendix B). All six checklists
are required for Immediate Occupancy (Critical or Essential VA buildings) located in areas of
High seismicity.
Most building data used in the seismic risk assessments of this study are taken directly from the
evaluation reports. In some cases, building data are derived from evaluation report data. For
example, the number of occupants (not known typically) is derived from the use (occupancy
type) and square footage of the building of interest, based on the number of occupants per square
foot typical of the given occupancy. In addition to direct and derived data, certain qualitative
data are inferred from evaluation reports including "seismic performance" and "data quality"
ratings of structural and nonstructural systems, respectively. For example, if an evaluation report
did not investigate nonstructural components, then these components are given a "seismic
performance" rating typical of similar VA buildings for which nonstructural data are available,
and assigned the lowest rating of "data quality."
2.2
Data Parameters and Sources
Facility data (e.g., location, site conditions), general building data (e.g., building type and size,
etc.) and performance-related data (e.g., seismic properties, etc.) required for risk assessment,
and their respective sources, are summarized in Tables 2-1, 2-2 and 2-3, respectively.
Table 2-1 Summary of facility data and sources
No.
Data Description
Data Source
1
Vision No.
VA Summary Sheet
2
Medical Center Name
VA Summary Sheet
3
Site Location
Latitude
ASCE 31 Summary Sheet
4
Site Location
Longitude
ASCE 31 Summary Sheet
5
Site Condition (Class)
VA Summary Sheet
6
Seismicity (H-18-08)
VA Summary Sheet
2-2
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 2-2 Summary of general building data and sources
No.
Data Description
Data Source
1
Building No.
VA Summary Sheet
2
Building Name
VA Summary Sheet
3
Occupancy - VA Sub-Name
Table 2-4
4
Occupancy Class - HAZUS
Table 2-4
5
Year of Construction
VA Summary Sheet
6
Year of Remodel
VA Summary Sheet
7
Building Size
Area (sq. ft.)
VA Summary Sheet
8
Building Size
Total Height (ft.)
VA Summary Sheet
9
Number of Stories
Above Grade
VA Summary Sheet
10
Number of Stories
Below Grade
VA Summary Sheet
11
Model Bldg. Type - HAZUS
12
Number of Occupants
Peak
Table 2-5
13
Number of Occupants
ECO
Table 2-5
14
Number of Approved Beds
15
Replacement Cost (RC)
Dollars
Table 2-6
16
Contents Cost
Dollars
Table 2-6
ASCE 31 Summary Sheet
Table 2-5
Table 2-3 Summary of performance related building data and sources
No.
Data Description
Data Source
1
Design Coefficient, Cs
HAZUS
Derived - ASCE 31 calculations
2
Seismic Design Level
HAZUS
Table 2-7
3
Seismic Performance Rating
Structure
Table 2-8
3
Seismic Performance Rating
NSD Systems
Table 2-9
5
Seismic Performance Rating
NSA Systems
Table 2-9
6
Seismic Performance Rating
Contents
Table 2-9
7
Quality of Data Rating
Structure
Table 2-10
8
Quality of Data Rating
NSD Systems
Table 2-10
9
Quality of Data Rating
NSA Systems
Table 2-10
10
Quality of Data Rating
Contents
Table 2-10
11
Structural Deficiencies
See Section 2.3
12
Nonstructural Deficiencies
See Section 2.4
2-3
Seismic Risk Assessment of VA Hospital Buildings
2.2.1
Phase I Report- Approach and Methods
April 13, 2010
Occupancy Class
A variety of occupancy classes of VA buildings are defined in Table 1 (for critical and essential
facilities) and Table 2 (for ancillary facilities) of Seismic Design Requirements, H-18-08 (DVA,
2008). In contrast, HAZUS methods have only one "hospital" occupancy category (COM6)
which is intended for acute care facilities. Other HAZUS occupancy categories are more
appropriate for VA hospital buildings used for other purposes than acute care. Table 2-4 shows
the scheme used to relate VA building occupancy classification to the HAZUS occupancy
category deemed to best represent the use of the building. Note. Long-term care and medical
research buildings are assigned special HAZUS occupancy categories (COM6A and COM7A),
respectively, to permit more appropriate values of the number of occupants and replacement cost
than the HAZUS default values.
2.2.2
Number of Occupant and Beds
Table 2-5 provides default values of the number of occupants and beds per 1,000 square feet of
building area typical of each occupancy category. Default values of occupants and beds per unit
area are used with building square footage to estimate the number of occupants and beds when
actual numbers are not known. Default values of beds per 1,000 square feet of building area are
based on a survey of representative buildings at VA facilities for which the number of beds is
actually known. Default values of occupants per 1,000 square feet of building area are based
loosely on building population models of ATC-58 (ATC, 2009, 50% draft). Note. Peak
occupants represent the maximum number of either daytime or night time occupants in the
building, and ECO (effective continuous occupancy) reflects the average number of occupants in
the building on a long-term basis.
2.2.3
Replacement Costs
Table 2-6 provides default values of the replacement cost of the building per square foot and the
default value of contents (percentage of building replacement cost without contents) for each
occupancy class. Default values of unit replacement costs are used with building square footage
to estimate the value of structural and nonstructural systems, respectively, when the actual value
of the building is not known. Similarly, the costs of contents are based on default values
(percentages) when actual values are not known.
Default values of replacement cost are based roughly on 2 times HAZUS values (or 3 times
HAZUS values for COM 6 and COM7A occupancies) given in Table 3.6 of the HAZUS
Technical Manual. Note. HAZUS values of unit cost (2002 vintage) are generally low and not
consistent with current (2009) hospital construction costs. Note also. Default values are the
same for all regions (i.e., considered too approximate to reflect regional differences).
Distribution of total building replacement cost between the structure (STR), nonstructural driftsensitive systems (NSD) and nonstructural acceleration-sensitive systems (NSA) is based on
Tables 15.2, 15.3 and 15.4, respectively, of the HAZUS Technical Manual. The additional cost
of contents (percentage of total building cost) is based on Table 3.10 of the HAZUS Technical
Manual, except the percentage for the COM6A is assumed to be 100% (rather than 150%).
2-4
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 2-4 Occupancy mapping scheme used to relate VA building use (occupancy
classification) to HAZUS Occupancy Classes
VA Hospital Building Occupancy Sub-Name1
Ancillary Facilities
HAZUS
Occupancy2
Dormitory/Student Housing
RES5
Critical and Essential Facilities
RES6
Domiciliary, Long-Term Care/Nursing Home
Storage (Hazardous Material, Medical Equipment,
Medical Gas, Utility Supply)
Offices (Medical Records, National Continuity of
Operations Center)
Retail Store, Canteen
COM1
Wharehouse
COM2
Maintenance Shops,
Biomedical Engr. (Repair)
COM3
Offices (General
Administration, Clinical
Services, Credit Union)
COM4
Bank/Credit Union
COM5
3
COM6
Hospital, Acute Care
Long-Term Care - Ambulatory Care, Mental Health4,5
Outpatient Clinic, Drug/Alcohol Rehabilitation,
Psychiatric Care Facility, Rehabilitation/Prosthetics6
COM6A
Community-Based Outpatient
Clinic
Medical Research, Animal Facility, Dietetics, Pharmacy,
Rehabilitation Medicine
Boiler Plant, Emergency Generator
COM7
COM7A
Recreational
COM8
Auditorium
COM9
Parking
COM10
Waste Management
IND2
Post Office
GOV1
Emergency Command Center, Communications Center,
Fire and Police Stations, Information Technology, Security
and Law Enforcement
GOV2
Educational, School,
Training, Library/Museum
EDU1
1. Occupancy Sub-Names as defined by Table 1 (Critical and Essential Facilities) and Table 2 (Ancillary
Facilities) of "Seismic Design Requirements" (DVA H-18-8, July 2008). Primary VA occupancy sub-name
of each class is shown in bold (i.e., names used in RCT)
2. HAZUS Building Occupancy Classes (HAZUS TM Table 3.2)
3. Occupancy class primarily used for in patient care (w/beds)
4. Occupancy class primarily used for in patient care (w/beds) that do not fit either Hospital (COM6) or
Domiciliary (RES6) occupancy classes
5. Long-Term Care building replacement cost assumed to be less than Hospital building replacement cost
6. Occupancy class used primarily for out patient care (buildings w/o beds)
2-5
Seismic Risk Assessment of VA Hospital Buildings
Table 2-5
Phase I Report- Approach and Methods
April 13, 2010
Default values of occupants and beds per 1,000 square feet of building area
for various occupancy categories
Occupancy Class
Building Use
at VA Facility
Default Occupants1
(per 1,000 sf)
HAZUS
Peak
ECO
Default Beds1
(per 1,000 sf)
Dormitory
RES5
8
5
3
Domiciliary
RES6
8
5
3
Retail
COM1
10
5
Storage
COM2
1
1
Maintenance
COM3
4
2
Offices
COM4
8
4
Bank
COM5
8
4
Hospital
COM6
4
2.5
1
Long-Term Care
COM6A
5
4
1
Outpatient Clinic
COM7
10
5
COM7A
10
5
Recreational
COM8
15
1
Auditorium
COM9
30
1
Parking
COM10
5
1
Boiler Plant
IND2
1
1
Post Office
GOV1
4
2
Emergency
GOV2
5
3
Educational
EDU1
12
2
Medical Research
1. Default number of occupants and beds (per 1,000 sf) for RES6, COM6/COM6A,
COM7/COM7A and IND2 occupancies based on data provided by the DVA
2-6
Seismic Risk Assessment of VA Hospital Buildings
Table 2-6
Phase I Report- Approach and Methods
April 13, 2010
Default values of replacement costs per square foot and contents values (as a
fraction of building value) for various occupancy categories
Occupancy Class
Building Use
at VA Facility
HAZUS
Fraction (% of Total)2
HAZUS
(2002)1
Default
Value4
STR
NSA
NSD
CON
Value3
(% of
Total)
Value w/o CON ($/sf)
Building w/o CON
Dormitory
RES5
$118.82
$350
18.8%
41.2%
40.0%
50%
Domiciliary
RES6
$104.63
$450
18.4%
40.8%
40.8%
50%
Retail
COM1
$83.59
$250
29.4%
43.1%
27.5%
50%
Storage
COM2
$70.43
$225
32.4%
41.1%
26.5%
100%
Maintenance
COM3
$86.81
$250
16.2%
50.0%
33.8%
100%
Offices
COM4
$102.69
$300
19.2%
47.9%
32.9%
100%
Bank
COM5
$153.97
$450
13.8%
51.7%
34.5%
100%
Hospital
COM6
$144.60
$650
14.0%
51.3%
34.7%
100%
Long-Term Care
COM6A
$144.60
$550
14.0%
51.3%
34.7%
100%
Outpatient Clinic
COM7
$129.82
$550
14.4%
51.2%
34.4%
100%
COM7A
$129.82
$750
14.4%
51.2%
34.4%
100%
Recreational
COM8
$135.23
$300
10.0%
54.4%
35.6%
100%
Auditorium
COM9
$109.60
$300
12.2%
52.7%
35.1%
100%
Parking
COM10
$49.20
$150
60.9%
21.7%
17.4%
50%
Boiler Plant
IND2
$78.61
$1,200
15.7%
72.5%
11.8%
0%
Post Office
GOV1
$86.83
$250
17.9%
49.3%
32.8%
100%
Emergency
GOV2
$136.10
$400
15.3%
50.5%
34.2%
100%
Educational
EDU1
$112.19
$350
18.9%
32.4%
48.7%
100%
Medical Research
1. HAZUS TM Table 3.6 (maximum of range)
2. HAZUS TM Table 15.2 (STR), Table 15.3 (NSA), and Table 15.4 (NSD)
3. HAZUS TM Table 3.10 (except contents limited to 100%, and 0% for Boiler Plant)
4. Replacement cost ($/sf) based on about 3 x HAZUS (2002), except cost data for RES 6,
COM6/COM6A, COM7/COM7A and IND2 occupancies provided by th DVA
2-7
Seismic Risk Assessment of VA Hospital Buildings
2.2.4
Phase I Report- Approach and Methods
April 13, 2010
Seismic Design Level and Design Coefficient (Cs)
The HAZUS classification of the seismic design level (High-Code. Moderate-Code, Low-Code
or Pre-Code design level) and related value of the seismic design coefficient, Cs, play a critical
role in determining building performance. The seismic design coefficient is used to define
building strength (capacity), as described in Chapter 4, and the seismic design level is used to
determine median values of damage states, as described in Chapter 5. Note. For risk
assessment, the value of seismic design coefficient, Cs, is that which was used to design the
original structure, not the value required by ASCE 31 for building evaluation, nor the value that
would be required today for design of a new building. For buildings not designed for seismic
loads (e.g., older building in regions of moderate or lower seismicity, or buildings for which
wind loads governed lateral forces), an "effective" value of the seismic design coefficient is used
to define building strength (capacity).
Tables A6-2a and A6-2b of the OSHPD (SB 1953) regulations, which apply only to California
hospitals, prescribe values of the seismic design coefficient as a function of building age,
structural system (model building type) and Seismic Zone 3 or 4, respectively, of the Uniform
Building Code (i.e., basis for California building codes). The VA risk assessment project has a
much broader scope, since VA hospital facilities are located throughout the United States and
VA buildings could have been designed (or not) for earthquakes using anyone of many different
building codes. Rather than attempting to emulate generic Tables A6-2a and A6-2b of the
OSHPD regulations (and almost impossible task), the VA risk assessment project assigns a value
to the seismic design coefficient to each of the (52) buildings in the scope. Values of the seismic
design coefficient are assigned considering the age of the building and lateral force design
requirements of the likely building code of the region, and other relevant information available
from ASCE 31 evaluation reports (e.g., the actual pushover strength of structure, if known).
Table 2-7 provides guidance for selecting seismic design level (HAZUS), considering the age
(year of construction), location (seismicity) and the value of the seismic design coefficient.
Table 2-7. Guidelines for selection of the HAZUS Seismic Design Level (adapted from
Table 5.20 of the HAZUS Technical Manual, NIBS, 2002)
Building Design Vintage
2
Seismicity
(H-18-08)
Example
1
Values, Cs
Post-1975
1960-1975
1941-1960
Pre-1941
Very High
≥ 0.14
Special High
Moderate
Low
Low
High
0.105 - 0.14
High
Moderate
Low
Pre-Code
Moderate-High
0.053 - 0.105
Moderate
Low
Pre-Code
Pre-Code
Moderate-Low
0.0265 - 0.053
Low
Pre-Code
Pre-Code
Pre-Code
Low
<0.0265
Pre-Code
Pre-Code
Pre-Code
Pre-Code
1. Example values of Cs include site effects (stiff soil) and represent a short-period "box"
system, e.g., Cs = CS, k = 1 (1976 UBC), Cs = Ca, R = 6.5 (1997 UBC)
2. For W1 buildings, use Low in lieu of Pre-Code, and Moderate in lieu of Low.
2-8
Seismic Risk Assessment of VA Hospital Buildings
2.2.5
Phase I Report- Approach and Methods
April 13, 2010
Seismic Performance Rating
Sections 2.3 and 2.4 describe structural and nonstructural deficiencies, identified by seismic
evaluations, and their use in risk assessments. Certain structural deficiencies, considered
"significant" with respect to building performance and specifically building collapse are used to
adjust "baseline" values of various capacity, response and damage and/or collapse rate
parameters to reflect sub-baseline (SubB) or ultra-sub-baseline (USB) performance similar to
OSHPD (SB 1953) regulations. Note. The somewhat awkward nomenclature, SubB and USB
are used for consistency with the terminology of the OSHPD (SB 1953) regulations.
In general, baseline properties are taken from HAZUS (i.e., so-called "default" properties of the
HAZUS methodology), and SubB or USB structural properties represent a substantial reduction
in seismic performance from that typical of the type, age and seismic design level of the building
of interest. Twenty-two (22) structural deficiencies (from a list of over 150) are considered
significant enough (e.g., with respect to building collapse performance) to warrant adjustment of
specific values of capacity, response and damage parameters (see Section 2.3). Other structural
deficiencies are considered important to building functional and economic losses, when
considered in a cumulative sense.
To account for the collective effect of all relevant structural deficiencies on building loss, a
"general" seismic performance rating (Item 3 of Table 2-3) is assigned to the structural system
and used to select loss parameters that reflect Baseline, Poor, or Very Poor performance of the
system of interest. General seismic performance of the structural system is rated in accordance
with Table 2-8.
Table 2-8
Seismic performance rating scheme for the structural system
Seismic
Performance
Rating
Number of Significant
Deficiencies (Table 2-11)
Qualitative Description of
Anticipated Risk Seismic
Performance (for MCE ground
motions)
Collapse Related
(Tables 2-11a - 2-11c)
Other
Baseline
None (Baseline)
Few
Low risk of collapse - moderate risk of
functional/economic losses
Poor
None (Baseline)
Many
1 (SubB)
Few
Moderate/high risk of collapse - High risk
of functional and economic losses
> 1 (USB)
NA
Very Poor
Very high risk of collapse and loss
Table 2-8 criteria effectively rates seismic performance in terms collapse-related deficiencies,
downgraded if there is a substantial number of additional structural deficiencies. Table 2-8
provides qualitative descriptions of anticipated performance for Baseline, Poor and Very Poor
ratings, respectively. For example, Baseline performance (which has no collapse-related
deficiencies and few, if any, other significant deficiencies) is expected to perform in a manner
comparable to a "benchmark" building of ASCE 31. As defined in Table 3-1 of ASCE 31,
benchmark buildings are designed in accordance with seismic code provisions assumed to
provide acceptable life safety performance (although they may not be functional as required of
2-9
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
hospital buildings after an earthquake). In contrast, buildings with a structural system rated as
Poor or Very Poor performance (i.e., buildings that have some combination of collapse-related
and other structural deficiencies) have significantly higher life-safety risk than benchmark
buildings, and would be expected to take longer and cost more to repair than Baseline buildings.
Similar to the structural system, general seismic performance ratings are assigned to driftsensitive nonstructural (NSD) components, acceleration-sensitive nonstructural (NSA)
components and contents (CON), respectively, and used to select values of loss parameters to
reflect Baseline, Poor or Very Poor performance, respectively. General seismic performance of
nonstructural components and contents is rated in accordance with Table 2-9 criteria considering
the number of significant deficiencies specified in Table 2-12 of Section 2.4.
Table 2-9
Seismic performance rating scheme for nonstructural components and contents
Qualitative Description of Risk/Seismic Performance
Seismic
Performance
Rating
Drift-Sensitive
Components
Acceleration-Sensitive
Components and Contents
Baseline
Approx. 2% drift capacity
Generally braced and anchored
Poor
Approx. 1% drift capacity
Partially braced and anchored
Approx. 0.5 % drift capacity
Little or no anchorage or bracing
Very Poor
2.2.6
Data Quality Rating
The quality of data used to define capacity and response parameters affects the uncertainty in
damage estimates (and related losses). Data quality naturally varies as a function of the level
analysis of the seismic evaluation of the building, ranging from Very Good for the more
sophisticated and detailed levels of analysis to Very Poor for systems not investigated (e.g., some
building evaluations did not investigate nonstructural systems). To account for the inherent
differences in the quality of the data, a data quality rating of Best, Very Good, Good, Poor, or
Very Poor is assigned to the structural system, drift-sensitive nonstructural components and
acceleration-sensitive nonstructural components and contents, respectively, in accordance with
the guidelines of Table 2-10. These data quality ratings influence the lognormal standard
deviation values of damage functions, as discussed in Chapter 5.
Table 2-10
Data quality rating scheme
Seismic Evaluation Data
Rating
Analysis Level
Best
Tier 3 (NDA)
Comments
Very high confidence in damage/loss parameters
Very Good
Tier 3
High confidence in damage/loss parameters
Good
Tier 2
Average confidence in damage/loss parameters
Poor
Tier 1 only
Very Poor
None
Low confidence in damage/loss parameters
Very low confidence (e.g., system not investigated)
2-10
Seismic Risk Assessment of VA Hospital Buildings
2.3
Phase I Report- Approach and Methods
April 13, 2010
Structural Deficiencies
Structural deficiencies identified by ASCE 31 building evaluations and documented on structural
checklists (by Degenkolb) are used to adjust various capacity, response, damage and collapse
rate parameters, in a manner similar to the OSHPD (SB 1953) regulations (Appendix A), and to
establish a general seismic performance rating for the structural system, as described in Section
2.2.5. Seismic performance ratings (Baseline, Poor or Very Poor) follow the criteria of Table 28, and are used to determine various loss rates as described in Chapter 6.
Structural checklists include items pertinent to the building system, the seismic-force-resisting
system, diaphragms and connections, respectively. Degenkolb Engineers has tailored ASCE 31
checklists to include only those items pertinent to the lateral-force-resisting system (model
building type) of the building of interest. Further, there is a basic checklist and supplementary
checklist for each model building type, a total of 20 plus structural checklists. Collectively, these
checklists contain over 150 individual items (potential structural deficiencies) as defined by
ASCE 31.
Tables 2-11a, 2-11b and 2-11c list the twenty-two (22) structural deficiencies (of the over 150
total structural deficiencies) that are considered most significant with respect to building collapse
performance and which are used to adjust various HAZUS parameters. Table 2-11a identifies
structural deficiencies used to adjust values of building capacity and response parameters
(Chapter 4). Table 2-11b identifies structural deficiencies used to adjust structural damage
(fragility) parameters (Chapter 5). Table 2-11c identifies structural deficiencies used to adjust
collapse rates (Chapter 6).
In Tables 2-11a - 2-11c, HAZUS parameters related to the significant structural deficiency of
interest are shown with an "x" indicating that the values of the respective parameter should be
based on either sub-Baseline (SubB) or ultra-sub-Baseline (USB) properties, respectively. As
discussed previously, mapping of collapse-related structural deficiencies to HAZUS parameters
is based largely on the "Significant Structural Deficiency Matrix," Table A6-1 of the OSHPD
(SB 1953) regulations.
2-11
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 2-11a. Structural deficiency mapping scheme - HAZUS capacity and response parameters
influenced by building system deficiencies and special OSHPD (SB 1953) criteria.
ASCE 31 Basic and Supplemental
Structural Checklist
(Degenkolb)
OSHPD
(CBC Reqt.
No.)
Capacity
Response
Over-Strength
Duration
Gamma and Lambda
Factors
Degradation (Kappa)
Factor
USB7
SubB
3.7.1
X
X
3.7.3
X
X
Deterioration of Concrete - Material
3.7.4
X
X
4.3.3.5
Post-Tensioning Anchors - Material
3.7.5
X
X
4.3.3.6
Precast Concrete Walls - Material
3.7.8
X
X
Type
No.
Description
SubB
Basic
4.3.2.1
Weak Story - Configuration
3.3.1
Basic
4.3.2.2
Soft Story - Configuration
3.3.2
Basic
4.3.2.4
Vertical Discontinuities - Configuration
3.3.5
Basic
4.3.2.5
Mass - Configuration
3.3.4
Basic
4.3.2.6
Torsion - Configuration
3.3.6
Basic
4.3.3.1
Deterioration of Wood - Material Cond.
Basic
4.3.3.3
Deterioration of Steel - Material Cond.
Basic
4.3.3.4
Basic
Basic
USB5
Building System
X
Lateral-Force-Resisting System
Basic
4.4.1.1.1
Redundancy - General
Supp.
4.4.1.3.6
Strong-Column Weak Beam - Steel MF
3.2
Supp.
4.4.1.4.5
Captive Columns - Concrete MF
Supp.
4.4.1.4.7
Strong Column/Weak Beam - Conc. MF
Supp.
4.4.1.6.2
Deflection Compatibility - Gravity
4.2.8
X
3.6
X
4.3.6
X
X
X
X
3.5
Basic
4.4.2.1.1
Redundancy - Shear Walls General
Basic
4.4.2.7.7
Cripple Walls - Walls in Wood Frame
3.2
Basic
4.4.3.1.1
Redundancy - Braced Frames General
Basic
4.5.5.1
Topping Slab - Precast Concrete Diaph.
5.6.4
3.2
Diaphragms
7.4.1
Connections
1.
Basic
4.6.1.1
Wall Anchorage - Normal Forces
8.2.1
X
Basic
4.6.1.2
Wood Ledgers - Normal Forces
8.2.2
X
Supp.
4.6.1.3
Precast Panel Connections - Normal
8.2.6
X
Sub-Baseline (SubB) and Ultra-Sub-Baseline (USB) properties are based on one, or more, significant structural
deficiencies.
2. The Deflection Incompatibility structural deficiency applies only to concrete systems (model building types: C1,
C2 and C3).
3. The Short Column structural deficiency applies only to concrete and masonry systems (model building types:
C1, C2, C3, RM1 and RM2).
4. Effects of deficiencies related to drift and mode shape limited to a combined factor of 5 reduction in Complete
median (of HAZUS default value).
5. Grey shading indicates USB performance is not defined/used for deficiencies related to degradation (kappa) and
fragility curve (beta) factors.
6. USB performance required for systems with multiple, SubBase deficiencies related to either the mode shape
(Alpha 3) factor or the collapse rate.
7. Loss rates based on general seismic performance rating (Baseline, Poor, or Very Poor) determined in accordance
with Table 2-8 criteria.
2-12
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 2-11b. Structural deficiency mapping scheme - HAZUS damage (fragility) parameters
influenced by building system deficiencies and special OSHPD (SB 1953) criteria
Structural Damage - Damage State
ASCE 31 Basic and Supplemental
Structural Checklist
(Degenkolb)
OSHPD
(CBC
Reqt.
No.)
Description
Fragility Curve Median4
Maximum Story
Drift Ratio (DC)
Mode Shape
(Alpha 3) Factor
SubB
SubB
USB6
Type
No.
USB
Basic
4.3.2.1
Weak Story - Configuration
3.3.1
X
X
X6
Basic
4.3.2.2
Soft Story - Configuration
3.3.2
X
X
X6
Basic
4.3.2.4
Vertical Discontinuities - Configuration
3.3.5
X
X
Fragility Curve
Variability - Beta
Factor (b C)
SubB
USB5
Building System
Basic
4.3.2.5
Mass - Configuration
3.3.4
Basic
4.3.2.6
Torsion - Configuration
3.3.6
Basic
4.3.3.1
Deterioration of Wood - Material Cond.
3.7.1
Basic
4.3.3.3
Deterioration of Steel - Material Cond.
3.7.3
Basic
4.3.3.4
Deterioration of Concrete - Material
3.7.4
Basic
4.3.3.5
Post-Tensioning Anchors - Material
3.7.5
Basic
4.3.3.6
Precast Concrete Walls - Material
3.7.8
Basic
4.4.1.1.1
Redundancy - General
Supp.
4.4.1.3.6
Strong-Column Weak Beam - Steel MF
Supp.
4.4.1.4.5
Captive Columns - Concrete MF
Supp.
4.4.1.4.7
Strong Column/Weak Beam - Conc. MF
Supp.
4.4.1.6.2
Basic
4.4.2.1.1
Basic
4.4.2.7.7
Cripple Walls - Walls in Wood Frame
Basic
4.4.3.1.1
Redundancy - Braced Frames General
X
Lateral-Force-Resisting System
3.2
4.2.8
X
X
3.6
X
4.3.6
X
Deflection Compatibility - Gravity
3.5
X
Redundancy - Shear Walls General
3.2
5.6.4
3.2
X
X
X
X
X6
X
Diaphragms
Basic
4.5.5.1
Topping Slab - Precast Concrete Diaph.
7.3.2
X
Connections
1.
Basic
4.6.1.1
Wall Anchorage - Normal Forces
8.2.1
Basic
4.6.1.2
Wood Ledgers - Normal Forces
8.2.2
X
X
Supp.
4.6.1.3
Precast Panel Connections - Normal
8.2.6
X
Sub-Baseline (SubB) and Ultra-Sub-Baseline (USB) properties are based on one, or more, significant structural
deficiencies.
2. The Deflection Incompatibility structural deficiency applies only to concrete systems (model building types: C1,
C2 and C3).
3. The Short Column structural deficiency applies only to concrete and masonry systems (model building types:
C1, C2, C3, RM1 and RM2).
4. Effects of deficiencies related to drift and mode shape limited to a combined factor of 5 reduction in Complete
median (of HAZUS default value).
5. Grey shading indicates USB performance is not defined/used for deficiencies related to degradation (kappa) and
fragility curve (beta) factors.
6. USB performance required for systems with multiple, SubBase deficiencies related to either the mode shape
(Alpha 3) factor or the collapse rate.
7. Loss rates based on general seismic performance rating (Baseline, Poor, or Very Poor) determined in accordance
with Table 2-8 criteria.
2-13
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 2-11c. Structural deficiency mapping scheme - HAZUS casualty and
other loss parameters influenced by building system and special
OSHPD (SB 1953) criteria.
Casualty Losses
ASCE 31 Basic and Supplemental
Structural Checklist
(Degenkolb)
OSHPD
(CBC Reqt.
No.)
Collapse Factor
(P[COL|STR5])
SubB
USB6
3.3.1
X
X6
3.3.2
X
X6
X
X6
3.2
X
X6
4.2.8
X
Type
No.
Description
Basic
4.3.2.1
Weak Story - Configuration
Basic
4.3.2.2
Soft Story - Configuration
Basic
4.3.2.4
Vertical Discontinuities - Configuration
3.3.5
Basic
4.3.2.5
Mass - Configuration
3.3.4
Basic
4.3.2.6
Torsion - Configuration
3.3.6
Basic
4.3.3.1
Deterioration of Wood - Material Cond.
3.7.1
Basic
4.3.3.3
Deterioration of Steel - Material Cond.
3.7.3
Basic
4.3.3.4
Deterioration of Concrete - Material
3.7.4
Basic
4.3.3.5
Post-Tensioning Anchors - Material
3.7.5
Basic
4.3.3.6
Precast Concrete Walls - Material
3.7.8
Building System
Lateral-Force-Resisting System
Basic
4.4.1.1.1
Redundancy - General
Supp.
4.4.1.3.6
Strong-Column Weak Beam - Steel MF
Supp.
4.4.1.4.5
Captive Columns - Concrete MF
Supp.
4.4.1.4.7
Strong Column/Weak Beam - Conc. MF
Supp.
4.4.1.6.2
Deflection Compatibility - Gravity
3.5
X
X6
Basic
4.4.2.1.1
Redundancy - Shear Walls General
3.2
X
X6
Basic
4.4.2.7.7
Cripple Walls - Walls in Wood Frame
5.6.4
X
X6
Basic
4.4.3.1.1
Redundancy - Braced Frames General
3.2
X
X6
7.3.2
X
X6
3.6
4.3.6
Diaphragms
Basic
4.5.5.1
Topping Slab - Precast Concrete Diaph.
Basic
4.6.1.1
Wall Anchorage - Normal Forces
8.2.1
Basic
4.6.1.2
Wood Ledgers - Normal Forces
8.2.2
Supp.
4.6.1.3
Precast Panel Connections - Normal
8.2.6
Connections
1.
2.
3.
4.
5.
6.
7.
Sub-Baseline (SubB) and Ultra-Sub-Baseline (USB) properties are based on one, or more,
significant structural deficiencies.
The Deflection Incompatibility structural deficiency applies only to concrete systems (model
building types: C1, C2 and C3).
The Short Column structural deficiency applies only to concrete and masonry systems (model
building types: C1, C2, C3, RM1 and RM2).
Effects of deficiencies related to drift and mode shape limited to a combined factor of 5 reduction
in Complete median (of HAZUS default value).
Grey shading indicates USB performance is not defined/used for deficiencies related to
degradation (kappa) and fragility curve (beta) factors.
USB performance required for systems with multiple, SubBase deficiencies related to either the
mode shape (Alpha 3) factor or the collapse rate.
Loss rates based on general seismic performance rating (Baseline, Poor, or Very Poor)
determined in accordance with Table 2-8 criteria.
2-14
Seismic Risk Assessment of VA Hospital Buildings
2.4
Phase I Report- Approach and Methods
April 13, 2010
Nonstructural Deficiencies
Nonstructural deficiencies identified by ASCE 31 building evaluations and documented
nonstructural checklists (by Degenkolb) are used to establish general seismic performance
ratings for drift-sensitive nonstructural (NSD) components, acceleration-sensitive nonstructural
(NSA) components, and contents (CON), respectively, as described in Section 2.2.
Nonstructural checklists include items pertinent to:
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
partitions,
ceiling systems,
light fixtures,
cladding and glazing,
masonry veneer,
metal stud back-up systems,
concrete and masonry back-up systems,
parapets, cornices, ornamentation and appendages,
masonry chimneys,
contents and furnishings,
mechanical and electrical equipment,
piping
ducts,
hazardous materials storage and distribution, and
elevators
Collectively, nonstructural checklists contain over 80 individual items (potential nonstructural
deficiencies) as defined by ASCE 31. Table 2-12 lists of each of the 80 plus checklist items,
identifying deficiencies considered significant in terms of building losses.
Table 2-12 indicates primary component type, NSD or NSA (or CON), used by HAZUS to group
components for valuation and estimation of damage to nonstructural systems. An "x" or "(x)" in
the NSD column indicates those nonstructural deficiencies considered in determining the general
seismic performance rating of NSD nonstructural components, and an "x" or "(x)" in the NSA
column indicates those nonstructural deficiencies considered in determining the general seismic
performance rating of NSA nonstructural components, and an "x" in the CON column indicates
those contents deficiencies considered in determining the general seismic performance rating of
contents. Note. In Table 2-12, use of parentheses indicates those deficiencies that are related to
the secondary component type of HAZUS. For example, bracing of unreinforced masonry
partitions (ASCE 31 Checklist Item No. 4.8.1.1) is shown in parentheses as an NSA-related
deficiency, since partition damage and loss is considered (by HAZUS) to be primarily related to
drift (NSD).
Seismic performance ratings (Baseline, Poor or Very Poor) follow the criteria of Table 2-9, and
are used to determine various loss rates as described in Chapter 6.
2-15
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 2-12. Nonstructural deficiencies that influence HAZUS nonstructural driftsensitive (NSD) components, nonstructural acceleration-sensitive (NSA)
components and contents (CON) loss parameters, respectively
ASCE 31 Basic, Intermediate or Supplemental
Nonstructural Component Checklist
(Degenkolb)
Description
Deficiencies Considered in
HAZUS
Determining General Seismic
Prmary
Performance Ratings for
(Secondary)
Nonstructural Components
Component
and Contents
Type
NSD
NSA
CON
Type
No.
Basic
Supp.
Supp.
Supp.
4.8.1.1
4.8.1.2
4.8.1.3
4.8.1.4
Basic
Inter.
Inter.
Inter.
Supp.
Supp.
4.8.2.1
4.8.2.2
4.8.2.3
4.8.2.4
4.8.2.5
4.8.2.6
Supp.
Inter.
Supp.
Supp.
4.8.3.1
4.8.3.2
4.8.3.3
4.8.3.4
Basic
Basic
Basic
Basic
Basic
Basic
Basic
Inter.
Supp.
4.8.4.1
4.8.4.2
4.8.4.3
4.8.4.4
4.8.4.5
4.8.4.6
4.8.4.7
4.8.4.8
4.8.4.9
Basic
Basic
Basic
Basic
Supp.
Supp.
Supp.
4.8.5.1
4.8.5.2
4.8.5.3
4.8.5.4
4.8.5.5
4.8.5.6
4.8.5.7
Supp.
Supp.
4.8.6.1
4.8.6.2
Supp.
Supp.
4.8.7.1
4.8.7.2
Anchorage (at 4 feet)
NSD
(NSA)
URM Back-Up (not permitted)
Parapets, Cornices, Ornamentation, and Appendages
Basic
Basic
Inter.
Inter.
4.8.8.1
4.8.8.2
4.8.8.3
4.8.8.4
URM Parapets (bracing required)
Canopies (anchoring at 6 feet)
Concrete Parapets (vert rebar required)
Appendages (anchorage at 6 feet - IO)
Partitions
Unreinforced Masonry (bracing)
Drift (0.02-flexible, 0.005-rigid SFRSs)
NSD
(NSA)
Strucutral Separations (seismic joints)
Tops (bracing)
Ceiling Systems
Support (as bracing for partitions)
Lay-In Tiles (secured w/clips at exits)
Integrated Ceilings (wires at exits)
NSA
Suspended Lath and Plaster (anchorage)
Edges (separation at walls)
Seismic Joints
Light Fixtures
Emergency Lighting
Independent Support (2 wires)
NSA
Pendant Supports (attachment)
Lens Covers (safety devices)
Cladding and Glazing
Cladding Anchors (anchorage)
Deterioration (of anchroages)
Cladding Isolation (0.02/0.01 drift)
Multistory Panels (0.02/0.01 drift)
NSD
Bearing Connections (2/panel)
(NSA)
Inserts (positive anchorage)
Panel Connections (4/panel out-of-plane)
Glazing (safety glass)
Glazing (safety glass)
Masonry Veneer
Shelf Angles (each floor)
Ties (at 2 feet)
Weakened Planes (anchorage)
NSD
Deterioration (of conections)
(NSA)
Mortar (quality)
Weep Holes (quality)
Stone Cracks (distress)
Metal Stud Back-Up Systems
Stud Tracks (anchorage)
NSD
(NSA)
Openings (frame around windows/doors)
ConcreteBlock and Masonry Back-Up Systems
2-16
NSA
(x)
x
x
(x)
x
x
x
x
(x)
(x)
x
x
(x)
(x)
(x)
x
(x)
(x)
(x)
(x)
(x)
x
x
x
x
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 2-12. Nonstructural deficiencies that influence HAZUS nonstructural driftsensitive (NSD) components, nonstructural acceleration-sensitive (NSA)
components and contents (CON) loss parameters, respectively (continued)
ASCE 31 Basic, Intermediate or Supplemental
Nonstructural Component Checklist
(Degenkolb)
Type
No.
Basic
Inter.
4.8.9.1
4.8.9.2
Basic
Basic
4.8.10.1
4.8.10.2
Basic
Inter.
Inter.
Inter.
Inter.
4.8.11.1
4.8.11.2
4.8.11.3
4.8.11.4
4.8.11.5
Basic
Basic
Basic
Basic
Inter.
Supp.
Supp.
Supp.
4.8.12.1
4.8.12.2
4.8.12.3
4.8.12.4
4.8.12.5
4.8.12.6
4.8.12.7
4.8.12.8
Basic
Basic
Supp.
Supp.
Supp.
4.8.13.1
4.8.13.2
4.8.13.3
4.8.13.4
4.8.13.5
Inter.
Supp.
Supp.
4.8.14.1
4.8.14.2
4.8.14.3
Basic
Supp.
Supp.
4.8.15.1
4.8.15.2
4.8.15.3
Supp.
Supp.
Supp.
Supp.
Supp.
Supp.
Supp.
Supp.
Supp.
4.8.16.1
4.8.16.2
4.8.16.3
4.8.16.4
4.8.16.5
4.8.16.6
4.8.16.7
4.8.16.8
4.8.16.9
Deficiencies Considered in
HAZUS
Determining General Seismic
Prmary
Performance Ratings for
(Secondary)
Nonstructural Components
Component
and Contents
Type
CON
NSD
NSA
Description
Masonry Chimneys
URM Chimneys (height limits)
NSA
Anchorage (at each floor)
Stairs
URM Walls (12-to1 h/t ratio limit)
NSD
(NSA)
Stair Details (accommodate drift)
Building Contents and Furnishings
Tall Narrow Contents (anchorage)
File Cabinets (anchored together)
NSA
Drawers (safety latches)
Access Floors (braced over 9 inches)
Equipment on Access Floors (anchored)
Mechanical and Electrical Equipment
Emergency Power (anchorage)
Hazardous Material Equipment (braced)
Deterioration (of anchorage)
Attached Equipment (braced)
NSA
Vibration Isolators (snubbers)
Heavy Equipment (anchored)
Electrical Equipment (braced)
Doors (0.01 drift)
Piping
Fire Suppression (anchored, NFPA-13)
Flexible Couplings (required)
NSA
Fluid and Gas Piping (anchorage)
(NSD)
Shut-Off Valves (required at interface)
C-Clamps (restraint)
Ducts
Stairs and Smoke Ducts (braced)
NSA
Duct Bracing (required for large ducts)
(NSD)
Duct Support (not permited by piping)
Hazardous Materials Storage and Distribution
Toxic Substances (container restraint)
NSA
Gas Cylinders (restraint)
(NSD)
Hardous Materials (piping shut-off)
Elevators
Support System (anchorage)
Seismic Switch (at 0.10g)
Shaft Walls (bracing)
Retainer Guards (cables)
NSA
Retainer Plate (car/counterweight)
(NSD)
Counterweight Rails (ASME A17.1)
Brackets (ASME A17.1)
Spreader Bracket (not allowed)
Go-Slow Elevators
2-17
x
x
(x)
x
x
x
x
x
x
x
x
x
x
(x)
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
CHAPTER 3. GROUND MOTION DATA
3.1
Introduction
This chapter describes the ground motion data used for risk evaluation of buildings located at the
28 VA facility sites listed in Table 1-1. 2 HAZUS methods require four intensity parameters to
describe each set of ground motion data: (1) peak ground acceleration (PGA) in units of gravity,
(2) peak ground velocity (PGV) in units of inches per second, (3) 0.3-second response spectral
acceleration (SA03) in units of gravity, and (4) 1.0-second response spectral acceleration (SA10)
in units of gravity. PGV is required for estimating damage and losses due to ground failure,
which is not in scope of this project: and values of PGV are not developed for VA facility sites.
There are a number of different types of ground motions that could be used for risk evaluation,
including the following:
Code Ground Motions - Code ground motions refer to the seismic criteria specified for design
of buildings by ASCE 7. Seismic criteria of ASCE 7 include two levels of ground
motions: (1) maximum considered earthquake (MCE) ground motions, and (2) Design
earthquake ground motions (defined as two-thirds of MCE ground motions). ASCE 7-05
is the edition of ASCE 7 required by the VA's Seismic Design Requirements (H-18-08,
2008). ASCE 7-10 is the new edition of ASCE 7 that incorporates the most current
seismic hazard information developed by the United States Geological Survey (USGS)
for the National Seismic Hazard Mapping Program (NSHMP). ASCE 7 seismic criteria
are based on complex combination of deterministic and probabilistic ground motions
deemed appropriate for building design by Code development committees and agencies
(e.g., Building Seismic Safety Council).
Probabilistic Ground Motions - Probabilistic ground motions refer to the seismic hazard
functions that incorporate various sources of uncertainty associated with earthquake
magnitude, occurrence rate, ground motion attenuation, etc. Whereas Code ground
motions are specified at only two intensity levels, hazard functions describe probabilistic
ground motions for all earthquake intensity levels (e.g., as a function of return period).
Probabilistic ground motions are required for calculation of average annualized loss
(AAL), which requires integration of hazard functions with conditional losses. The same
hazard functions developed by the USGS for the NSHMP and used to develop the new
Code ground motions of ASCE 7-10 are used as the basis for the probabilistic ground
motions of this project.
Deterministic Ground Motions - Deterministic ground motions refer to earthquake intensities
(e.g., median and 84th percentile) associated with the occurrence of a "maximum
magnitude" event on the fault governing seismic hazard at the facility site of interest.
Deterministic ground motions provide a basis for developing "worst case" estimates of
2
Ground motion data are also described for Memphis (614) - total of 29 medical center facility
sites.
3-1
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
damage and loss to buildings at the facility of interest, which can be used for emergency
response planning by facility management.
Scenario Earthquake Ground Motions - Scenario Earthquake ground motions refer to
earthquake intensities (e.g., median and 84th percentile) associated with the occurrence of
a "maximum magnitude" event on a major fault in the region (VISN) of interest. While
Scenario Earthquake ground motions are similar to Deterministic ground motion, they
would not necessarily be based on the same fault. Scenario Earthquake ground motions
provide a basis for developing "worst case" estimates of coincident damage and loss to
buildings at facilities in the region (VISN) of interest, that can be used for emergency
response planning on a regional basis.
While Code and Probabilistic ground motions are currently available from the USGS,
Deterministic and Scenario Earthquake ground motions are not, and would require considerable
effort to develop, which is not in the scope of this project. Code and Probabilistic ground
motions provide an adequate basis for comparative evaluation of building performance,
consistent with VA program goals (Section 1.2). The following sections describe development
and values of these two types of ground motions.
3.2
Code Ground Motions
Table 3-1 summarizes Code ground motion data obtained from USGS websites for ASCE 7-05
seismic criteria (http://earthquake.usgs.gov/designmaps/usapp/buildings) and for ASCE 7-10
seismic criteria (http://earthquake.usgs.gov/designmaps/usapp/). Values of short-period response
spectral acceleration (SS) and 1-second response spectral acceleration (S1), respectively, are listed
for each of 29 VA facility sites. These data represent MCE ground motions for an assumed Site
Class B and require modification for the actual site conditions of the facility of interest.
When compared to ASCE 7-05, ASCE 7-10 seismic criteria are significantly greater at some
sites, such as West Los Angeles, and significantly less at others, such as Long Beach, reflecting
changes to underlying seismic hazard data developed by the USGS. However, on average,
changes are relatively modest. For all 29 VA facility sites, 1-second ground motions have
increased slightly by about 2%, on average, and short-period ground motions have decreased by
about 9%, on average. There are clear regional trends. In the Northeast (represented by VISNs 1
and 3) and the New Madrid Zone (represented by VISNs 9, 15, 16), short-period ground motions
have come down by about 20%, on average, and in the Pacific Northwest (VISN 20), 1-second
ground motions have increased by about 15%, on average. These trends are the same as those
observed by Code development committees during development of the new ground motions.
While Code ground motions are developed for both ASCE 7-05 and ASCE 7-10 seismic criteria
(to permit comparison of new and existing ground motions), only Code ground motions of ASCE
7-10 are used for VA seismic risk evaluations.
Tables 3-2a and 3-2b develop values Code ground motions (Design and MCE) for each of the 29
VA facility based on ASCE 7-05 and ASCE 7-10 data, respectively. These tables summarize the
site class, the corresponding values of site factors (Fa and Fv), and values of MCE and Design
ground motions, respectively, for each VA facility. In general, site class data is available from
3-2
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
building seismic evaluation reports (Degenkolb). Site Class D is assumed (as indicated by the
values in parentheses in Tables 3-2a and 3-2b) for two facility sites that do not have available
site class data. In some cases, different values of site class are reported for different buildings at
the same facility site. While actual site conditions could be different, it is more likely that
different values simply reflect the inherent uncertainty associated with the site classification
process. In such cases, a "compromise" site class (e.g., CD) is assigned to the facility, and
interpolated values of the site factors used for risk evaluations.
As noted earlier, HAZUS requires values of PGA as well as 0.3-second and 1-second response
spectral acceleration. Consistent with ASCE 7 methods, Code values of PGA ground motions
are assumed to be 0.4 times the corresponding value of short-period response spectral
acceleration. Also, HAZUS theory defines the acceleration domain (short-period response) in
terms of 0.3-second response spectral acceleration, while ASCE 7 defines short-period response
by 0.2-second response spectral acceleration. In general, response spectral accelerations at
periods of 0.2 seconds and 0.3 seconds tend to be very similar, except for certain low hazard
regions of the CEUS for which 0.2-second response tends to greater than 0.3-second response.
For this project, Code ground motions are used, as defined by ASCE 7, for risk evaluations.
Table 3-3 summarizes the Kappa Index factors for each of the 29 VA facility sites. The Kappa
Index factor identifies the value of the Kappa factor (i.e., row in Table 4-7) used to calculate
peak inelastic response of the structure (Chapter 4). The larger the value of the Kappa Index
factor, the longer the duration of strong shaking; and the greater the degradation of the system
assumed for calculation of inelastic response. Ideally, Kappa Index factors would be based on
the maximum magnitude and fault distance (site to source) of the governing fault. The fault that
governs hazard at the facility site can be different for short-period and 1-second response,
respectively, and different ground motion intensities (e.g., different return periods of
Probabilistic ground motions). The default criteria of Table 4-7 (which are based on the VA
Seismicity Index) are used to determine values of the Kappa Index (and related Kappa factors),
since maximum magnitude and fault distance data are not available, and would require additional
site-specific hazard studies to develop.
3-3
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-1. List of 29 VA medical facilities, site location (latitude and longitude), and ASCE 705 and ASCE 7-10 ground motion parameters, SS and S1, of each facility, respectively
VA Medical Center
VISN
No.
Site Location
ASCE 7-051
ASCE 7-102
ID
No.
Facility Name
(City, State)
Latitude
Longitude
SS (g)
S1 (g)
SS (g)
S1 (g)
405
White River Junction, VT
43.6501
-72.3223
0.303
0.082
0.240
0.083
523
Boston, MA
42.3665
-71.0588
0.281
0.068
0.217
0.069
561
East Orange, NJ
40.7540
-74.2347
0.360
0.070
0.276
0.072
620
Montrose, NY
41.2371
-73.9324
0.334
0.070
0.253
0.071
630
New York, NY
40.7363
-73.9771
0.361
0.070
0.278
0.072
7
544
Columbia SC
33.9769
-80.9617
0.566
0.152
0.428
0.146
8
672
San Juan, PR
18.4659
-66.1134
0.893
0.310
0.997
0.398
614
Memphis, TN
35.1429
-90.0254
1.335
0.365
0.982
0.342
626
Nashville, TN
36.1415
-86.8038
0.347
0.133
0.304
0.146
1
3
9
15
657A5
Marion, IL
37.7298
-88.9558
1.128
0.309
0.898
0.306
16
598A0
North Little Rock, AR
34.7448
-92.3211
0.497
0.161
0.399
0.162
501
Albuquerque, NM
35.0554
-106.5776
0.566
0.171
0.453
0.136
649
Prescott, AZ
34.7533
-112.0487
0.331
0.100
0.310
0.091
436
Fort Harrison, MT
46.6146
-112.0928
0.679
0.199
0.535
0.155
463
Anchorage, AK
61.2112
-149.8271
1.498
0.558
1.500
0.679
648
Portland, OR
45.5234
-122.6762
0.983
0.345
0.983
0.422
653
Roseburg, OR
43.2233
-123.3650
0.825
0.419
0.832
0.444
663
Seattle, WA
47.5627
-122.3095
1.531
0.525
1.469
0.566
687
Walla Walla WA
46.0527
-118.3588
0.462
0.131
0.377
0.133
692
White City, OR
42.3176
-122.8333
0.576
0.258
0.609
0.325
663A4
American Lake, WA
47.1422
-122.5642
1.189
0.415
1.295
0.512
612
Martinez/NCSC, CA
37.9943
-122.1171
1.500
0.600
1.663
0.612
640
Palo Alto, CA
37.4040
-122.1412
1.994
0.803
1.815
0.773
654
Reno, NV
39.5163
-119.8005
1.504
0.605
1.831
0.618
662
San Francisco, CA
37.7810
-122.5052
1.841
0.952
1.969
0.925
600
Long Beach, CA
33.7757
-118.1189
1.687
0.640
1.570
0.584
664
San Diego, CA
32.8747
-117.2322
1.564
0.600
1.202
0.465
691A4
Sepulveda, CA
34.2454
-118.4811
2.085
0.742
2.241
0.735
West Los Angeles, CA
34.0532
-118.4579
1.867
0.636
2.226
0.824
18
19
20
21
22
692
1. Values obtained from USGS web site: http://earthquake.usgs.gov/designmaps/usapp/buildings
2. Values obtained from USGS web site: http://earthquake.usgs.gov/designmaps/usapp/
3-4
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-2a. List of 29 VA medical facilities, site coefficients (Fa and Fv), and Code MCE
ground motion parameters, SMS and SM1, and Code Design ground motion parameters (SDS
and SD1) of each facility based on ASCE 7-05 seismic criteria
VA Medical Center
VISN
No.
Site
Class1
Site
Coefficients
MCE
Design
Ground Motions Ground Motions
Fa
Fv
SMS (g)
SM1 (g)
SDS (g)
SD1 (g)
ID
No.
Facility Name
(City, State)
405
White River Junction, VT
D
1.56
2.40
0.47
0.20
0.32
0.13
523
Boston, MA
D
1.60
2.40
0.45
0.16
0.30
0.11
561
East Orange, NJ
D
1.52
2.40
0.55
0.17
0.36
0.11
620
Montrose, NY
D
1.56
2.40
0.52
0.17
0.35
0.11
630
New York, NY
E
2.15
3.50
0.78
0.25
0.52
0.16
7
544
Columbia SC
D
1.36
2.24
0.77
0.34
0.51
0.23
8
672
San Juan, PR
C
1.06
1.50
0.95
0.47
0.63
0.31
614
Memphis, TN
(D)
1.00
1.68
1.34
0.61
0.89
0.41
626
Nashville, TN
A
1.00
1.00
0.35
0.13
0.23
0.09
1
3
9
15
657A5
Marion, IL
DE
0.98
2.30
1.11
0.71
0.74
0.47
16
598A0
North Little Rock, AR
CD
1.32
1.90
0.66
0.31
0.44
0.20
18
19
20
21
22
501
Albuquerque, NM
D
1.36
2.16
0.77
0.37
0.51
0.25
649
Prescott, AZ
D
1.56
2.40
0.52
0.24
0.34
0.16
436
Fort Harrison, MT
E
1.40
3.25
0.95
0.65
0.63
0.43
463
Anchorage, AK
D
1.00
1.50
1.50
0.84
1.00
0.56
648
Portland, OR
CD
1.07
1.59
1.05
0.55
0.70
0.37
653
Roseburg, OR
C
1.08
1.40
0.89
0.59
0.59
0.39
663
Seattle, WA
D
1.00
1.50
1.53
0.79
1.02
0.53
687
Walla Walla WA
D
1.44
2.32
0.67
0.30
0.44
0.20
692
White City, OR
C
1.18
1.56
0.68
0.40
0.45
0.27
663A4
American Lake, WA
D
1.04
1.60
1.24
0.66
0.82
0.44
612
Martinez/NCSC, CA
D
1.00
1.50
1.50
0.90
1.00
0.60
640
Palo Alto, CA
(D)
1.00
1.50
1.99
1.20
1.33
0.80
654
Reno, NV
D
1.00
1.50
1.50
0.91
1.00
0.61
662
San Francisco, CA
D
1.00
1.50
1.84
1.43
1.23
0.95
600
Long Beach, CA
D
1.00
1.50
1.69
0.96
1.12
0.64
664
San Diego, CA
D
1.00
1.50
1.56
0.90
1.04
0.60
691A4
Sepulveda, CA
DE
0.95
1.95
1.98
1.45
1.32
0.96
D
1.00
1.50
1.87
0.95
1.24
0.64
692
West Los Angeles, CA
1. Site Class D (shown in parantheses) assumed, if actual site conditions ar not known.
3-5
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-2b. List of 29 VA medical facilities, site coefficients (Fa and Fv), and Code MCE
ground motion parameters, SMS and SM1, and Code Design ground motion parameters (SDS
and SD1) of each facility based on ASCE 7-10 seismic criteria
VA Medical Center
VISN
No.
Site
Class1
Site
Coefficients
MCE
Design
Ground Motions Ground Motions
Fa
Fv
SMS (g)
SM1 (g)
SDS (g)
SD1 (g)
ID
No.
Facility Name
(City, State)
405
White River Junction, VT
D
1.60
2.40
0.38
0.20
0.26
0.13
523
Boston, MA
D
1.60
2.40
0.35
0.17
0.23
0.11
561
East Orange, NJ
D
1.60
2.40
0.44
0.17
0.29
0.12
620
Montrose, NY
D
1.60
2.40
0.40
0.17
0.27
0.11
630
New York, NY
E
2.50
3.50
0.70
0.25
0.46
0.17
7
544
Columbia SC
D
1.48
2.24
0.63
0.33
0.42
0.22
8
672
San Juan, PR
C
1.02
1.42
1.02
0.57
0.68
0.38
614
Memphis, TN
(D)
1.12
1.72
1.10
0.59
0.73
0.39
626
Nashville, TN
A
1.00
1.00
0.30
0.15
0.20
0.10
1
3
9
15
657A5
Marion, IL
DE
1.13
2.30
1.01
0.70
0.68
0.47
16
598A0
North Little Rock, AR
CD
1.36
1.90
0.54
0.31
0.36
0.21
18
19
20
21
22
501
Albuquerque, NM
D
1.44
2.32
0.65
0.32
0.43
0.21
649
Prescott, AZ
D
1.56
2.40
0.48
0.22
0.32
0.15
436
Fort Harrison, MT
E
1.70
3.35
0.91
0.52
0.61
0.35
463
Anchorage, AK
D
1.00
1.50
1.50
1.02
1.00
0.68
648
Portland, OR
CD
1.07
1.48
1.05
0.62
0.70
0.42
653
Roseburg, OR
C
1.08
1.36
0.90
0.60
0.60
0.40
663
Seattle, WA
D
1.00
1.50
1.47
0.85
0.98
0.57
687
Walla Walla WA
D
1.52
2.32
0.57
0.31
0.38
0.21
692
White City, OR
C
1.16
1.48
0.71
0.48
0.47
0.32
663A4
American Lake, WA
D
1.00
1.50
1.30
0.77
0.86
0.51
612
Martinez/NCSC, CA
D
1.00
1.50
1.66
0.92
1.11
0.61
640
Palo Alto, CA
(D)
1.00
1.50
1.82
1.16
1.21
0.77
654
Reno, NV
D
1.00
1.50
1.83
0.93
1.22
0.62
662
San Francisco, CA
D
1.00
1.50
1.97
1.39
1.31
0.93
600
Long Beach, CA
D
1.00
1.50
1.57
0.88
1.05
0.58
664
San Diego, CA
D
1.02
1.54
1.23
0.72
0.82
0.48
691A4
Sepulveda, CA
DE
0.95
1.95
2.13
1.43
1.42
0.96
D
1.00
1.50
2.23
1.24
1.48
0.82
692
West Los Angeles, CA
1. Site Class D (shown in parantheses) assumed, if actual site conditions ar not known.
3-6
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-3. List of 29 VA medical facilities and default values of the Kappa Index used for risk
evaluations (i.e., vales of Mmax and df not available).
VA Medical Center
Controlling Source (Fault) Information
Short Period Reposne
1-Second Response
ID
No.
Facility Name
(City, State)
Max
Mag.,
Mmax
Min Dist.
to Fault,
df (km)
Kappa
Index1
Max
Mag.,
Mmax
Min Dist.
to Fault,
df (km)
Kappa
Index1
405
White River Junction, VT
NA
NA
9
NA
NA
9
523
Boston, MA
NA
NA
9
NA
NA
9
561
East Orange, NJ
NA
NA
8
NA
NA
8
620
Montrose, NY
NA
NA
9
NA
NA
9
630
New York, NY
NA
NA
8
NA
NA
8
7
544
Columbia SC
NA
NA
8
NA
NA
8
8
672
San Juan, PR
NA
NA
6
NA
NA
6
614
Memphis, TN
NA
NA
6
NA
NA
6
626
Nashville, TN
NA
NA
9
NA
NA
9
VISN
No.
1
3
9
15
657A5
Marion, IL
NA
NA
6
NA
NA
6
16
598A0
North Little Rock, AR
NA
NA
8
NA
NA
8
501
Albuquerque, NM
NA
NA
8
NA
NA
8
649
Prescott, AZ
NA
NA
9
NA
NA
9
436
Fort Harrison, MT
NA
NA
8
NA
NA
8
463
Anchorage, AK
NA
NA
6
NA
NA
6
648
Portland, OR
NA
NA
6
NA
NA
6
653
Roseburg, OR
NA
NA
6
NA
NA
6
663
Seattle, WA
NA
NA
6
NA
NA
6
687
Walla Walla WA
NA
NA
8
NA
NA
8
692
White City, OR
NA
NA
8
NA
NA
8
663A4
American Lake, WA
NA
NA
6
NA
NA
6
612
Martinez/NCSC, CA
NA
NA
6
NA
NA
6
640
Palo Alto, CA
NA
NA
6
NA
NA
6
654
Reno, NV
NA
NA
6
NA
NA
6
662
San Francisco, CA
NA
NA
6
NA
NA
6
600
Long Beach, CA
NA
NA
6
NA
NA
6
664
San Diego, CA
NA
NA
6
NA
NA
6
691A4
Sepulveda, CA
NA
NA
6
NA
NA
6
West Los Angeles, CA
NA
NA
6
NA
NA
6
18
19
20
21
22
692
1. Kappa Index based on default criteria (i.e., VA Seismicity Index) of Table 4.7
3-7
Seismic Risk Assessment of VA Hospital Buildings
3.3
Phase I Report- Approach and Methods
April 13, 2010
Probabilistic Ground Motions
Probabilistic ground motions are required for calculation of average annualized loss (AAL). For
this project, AAL is estimated by summing the damage or loss result of interest calculated at ten
(10) discrete levels of hazard, each weighted by the annual frequency of the respective hazard
level. This section develops the 10 discrete levels of ground motion intensity, and associated
annual probability (frequency) of occurrence, and corresponding probabilistic ground motions
for each of the 29 VA facility sites.
Table 3-4 summarizes the 10 discrete levels of ground motion intensity and associated annual
probability (frequency) of occurrence. As shown in the table, the return period (inverse of
annual frequency) ranges from 10 years to 9,975 years. Figure 3-1 illustrates the consistent
logarithmic relationship between return period and the annual probability associated with each
return period. Methods for calculating AAL using these discrete data are given in Section 6.1.2.
Tables 3-5a, 3-5b and 3-5c summarize probabilistic values of PGA, 0.3-second response spectral
acceleration and 1.0-second response spectral acceleration, respectively, for each of the 10 return
periods and for each of the 29 VA facility sites. These data represent ground motions in the
"maximum direction" of response, consistent with the new Code ground motions of ASCE 7-10.
Note. Prior studies of the HAZUS technology have shown that use of "maximum" ground
motions results in more reliable estimates of building damage and loss (Kircher et al., 2006).
The new probabilistic hazard data developed by the USGS for the NSHRP are not publicly
available (as of early 2010), and were obtained directly from the USGS (Luco, 2010). The
USGS probabilistic hazard data are based on the geometric mean intensity. Short period values
(i.e., PGA and 0.3-second response) are factored by 1.1, and 1.0 second response spectral
acceleration values are factored by 1.3 to approximate maximum direction response, consistent
with the methods used by the USGS to develop the new Code ground motions of ASCE 7-10.
All data in Tables 3-5a, 3-5b and 3-5c are based Site Class B conditions. Consequently,
comparisons with Code ground motions should be made with the data in Table 3-1 that also
represents Site Class B conditions. For example, the 1-second MCE response spectral
acceleration for the Roseburg VA facility (ID No. 653) is S1 = 0.444 g, and may be compared
with values of 1.0-second response spectral acceleration in row "653" of Table 3-5c. It may be
seen that MCE ground motions have an effective return period between 975 years (0.287 g) and
2,475 years (0.590 g), which is consistent with the new definition of "risk-targeted" MCE ground
motions of ASCE 7-10.
Risk evaluations require modification of the Site Class B ground motion data of Tables 3-5a, 35b and 3-5c, respectively. These adjustments are made in the RCT using the Code site factors, as
illustrated in Table 3-6 for the Roseburg VA facility site. Table 3-7 shows example Kappa Index
values for the Roseburg VA site used to the value of Kappa (degradation) factor. The default
criteria of Table 4-7 (which are based on the VA Seismicity Index) are used to determine values
of the Kappa Index (and related Kappa factors), since maximum magnitude and fault distance
data are not available, and would require additional site-specific hazard studies to develop.
3-8
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-4. Discrete levels of ground motion intensity and associated annual probability
(frequency) of occurrence used to characterize site hazard for calculation of average
annualized loss (AAL).
Discrete Ground Motion Intensity, i
Ground
Motion
GMi
Probability of Exceeding
Discrete Ground Motion Range
Return Period (years)
Return Period
(years)
Lower Bound Upper Bound
Annual
Probability
Pa[GMi]
50 Years
Annual
1
0.5%
1.00E-04
9,975
7,500
17,000
7.45E-05
2
1%
2.01E-04
4,975
3,500
7,500
1.52E-04
3
2%
4.04E-04
2,475
1,700
3,500
3.03E-04
4
5%
1.03E-03
975
750
1,700
7.45E-04
5
10%
2.11E-03
475
350
750
1.52E-03
6
20%
4.46E-03
224
170
350
3.03E-03
7
39%
1.00E-02
100
75
170
7.45E-03
8
63%
2.00E-02
50
35
75
1.52E-02
9
86%
4.00E-02
25
17
35
3.03E-02
10
99.3%
1.00E-01
10
7.5
17
7.45E-02
1.0E-01
Discrete RP Probability
Power (Discrete RP Probability)
Discrete RP Probability
1.0E-02
1.0E-03
1.0E-04
1.0E-05
10
100
1,000
10,000
Return Period (years)
Figure 3-1. Plot of probability of discrete intensity, defined in terms of return period
(RP), as a function of the return period.
3-9
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-5a. Peak ground acceleration data for 29 VA medical facilities for reference site
(Site Class B) conditions (USGS, 2008) factored by 1.1 to represent peak ground
acceleration in the maximum horizontal direction.
VISN
No.
Return Period (years)
ID
No.
9,975
4,975
2,475
975
475
224
100
50
25
10
405
0.320
0.208
0.134
0.074
0.046
0.027
0.014
0.008
0.004
0.001
523
0.336
0.211
0.129
0.065
0.037
0.020
0.010
0.005
0.002
0.001
561
0.485
0.304
0.180
0.083
0.043
0.020
0.008
0.004
0.002
0.001
620
0.442
0.274
0.162
0.075
0.040
0.020
0.009
0.004
0.002
0.001
630
0.496
0.311
0.184
0.084
0.042
0.020
0.008
0.004
0.002
0.001
7
544
0.520
0.368
0.256
0.147
0.084
0.039
0.016
0.007
0.003
0.001
8
672
0.663
0.548
0.446
0.326
0.247
0.180
0.122
0.084
0.057
0.034
614
1.150
0.870
0.627
0.356
0.182
0.065
0.025
0.011
0.005
0.001
626
0.278
0.215
0.161
0.098
0.058
0.030
0.015
0.009
0.004
0.002
15
657A5
1.014
0.767
0.559
0.335
0.194
0.086
0.035
0.016
0.006
0.002
16
598A0
0.436
0.319
0.228
0.132
0.071
0.028
0.012
0.006
0.003
0.001
501
0.400
0.295
0.206
0.120
0.077
0.046
0.026
0.014
0.006
0.002
649
0.270
0.197
0.141
0.087
0.058
0.036
0.020
0.011
0.005
0.001
436
0.423
0.322
0.238
0.153
0.105
0.068
0.042
0.026
0.016
0.006
463
1.035
0.895
0.757
0.594
0.476
0.366
0.264
0.192
0.135
0.078
648
0.782
0.615
0.467
0.310
0.213
0.132
0.069
0.036
0.018
0.005
653
0.886
0.655
0.459
0.249
0.125
0.054
0.028
0.016
0.008
0.002
663
1.121
0.878
0.671
0.455
0.328
0.226
0.143
0.090
0.052
0.020
687
0.350
0.256
0.181
0.109
0.071
0.045
0.025
0.014
0.006
0.002
692
0.554
0.424
0.312
0.190
0.119
0.069
0.039
0.024
0.013
0.004
663A4
0.884
0.726
0.589
0.426
0.319
0.226
0.145
0.091
0.052
0.020
612
1.209
1.022
0.861
0.653
0.511
0.381
0.261
0.174
0.103
0.039
640
1.327
1.124
0.924
0.679
0.510
0.359
0.233
0.155
0.097
0.044
654
1.195
0.968
0.767
0.525
0.367
0.239
0.143
0.089
0.052
0.023
662
1.583
1.337
1.109
0.822
0.616
0.414
0.239
0.142
0.082
0.034
600
1.028
0.837
0.658
0.460
0.337
0.239
0.161
0.112
0.073
0.036
664
0.986
0.774
0.577
0.346
0.221
0.144
0.095
0.066
0.046
0.026
691A4
1.327
1.124
0.928
0.691
0.528
0.379
0.246
0.157
0.091
0.038
692
1.511
1.221
0.949
0.650
0.467
0.321
0.206
0.135
0.083
0.037
1
3
9
18
19
20
21
22
3-10
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-5b. 0.3-second response spectral acceleration data for 29 VA medical facilities reference site (Site Class B) conditions (USGS, 2008) factored by 1.1 to represent
short-period response spectral acceleration in the maximum horizontal direction.
VISN
No.
Return Period (years)
ID
No.
9,975
4,975
2,475
975
475
224
100
50
25
10
405
0.477
0.335
0.231
0.137
0.088
0.053
0.029
0.016
0.008
0.002
523
0.462
0.310
0.203
0.112
0.069
0.039
0.020
0.010
0.005
0.001
561
0.606
0.392
0.245
0.124
0.070
0.037
0.017
0.009
0.004
0.001
620
0.557
0.362
0.229
0.119
0.070
0.038
0.019
0.009
0.004
0.001
630
0.615
0.396
0.247
0.124
0.070
0.037
0.017
0.008
0.004
0.001
7
544
0.816
0.610
0.441
0.254
0.145
0.069
0.030
0.013
0.005
0.001
8
672
1.274
1.044
0.846
0.612
0.462
0.332
0.220
0.150
0.100
0.057
614
1.888
1.446
1.060
0.590
0.287
0.107
0.044
0.021
0.009
0.002
626
0.579
0.467
0.352
0.219
0.128
0.067
0.034
0.018
0.009
0.002
15
657A5
1.622
1.246
0.925
0.553
0.310
0.137
0.059
0.028
0.012
0.002
16
598A0
0.786
0.601
0.443
0.255
0.135
0.057
0.025
0.012
0.005
0.001
501
0.817
0.589
0.407
0.236
0.151
0.093
0.052
0.029
0.013
0.002
649
0.516
0.378
0.272
0.169
0.114
0.072
0.042
0.023
0.010
0.001
436
0.816
0.618
0.457
0.293
0.203
0.135
0.084
0.054
0.032
0.013
463
2.122
1.831
1.521
1.175
0.916
0.690
0.489
0.353
0.243
0.135
648
1.576
1.224
0.932
0.614
0.418
0.256
0.134
0.071
0.035
0.010
653
1.744
1.307
0.935
0.522
0.263
0.120
0.062
0.034
0.016
0.001
663
2.290
1.742
1.299
0.858
0.609
0.414
0.258
0.162
0.094
0.038
687
0.649
0.474
0.336
0.206
0.138
0.088
0.051
0.029
0.013
0.000
692
1.133
0.868
0.642
0.387
0.240
0.141
0.080
0.048
0.027
0.008
663A4
1.693
1.378
1.108
0.789
0.585
0.410
0.260
0.163
0.093
0.036
612
2.610
2.195
1.804
1.345
1.046
0.762
0.510
0.335
0.195
0.075
640
2.946
2.458
1.955
1.391
1.024
0.706
0.451
0.297
0.184
0.084
654
2.674
2.138
1.660
1.096
0.744
0.474
0.280
0.173
0.102
0.045
662
3.696
3.036
2.474
1.749
1.258
0.822
0.469
0.278
0.159
0.067
600
2.181
1.729
1.333
0.913
0.666
0.472
0.318
0.220
0.145
0.071
664
2.093
1.610
1.149
0.669
0.431
0.287
0.192
0.137
0.095
0.054
691A4
2.953
2.480
2.000
1.457
1.096
0.765
0.486
0.305
0.176
0.075
692
3.259
2.581
1.977
1.328
0.943
0.640
0.406
0.264
0.161
0.073
1
3
9
18
19
20
21
22
3-11
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-5c. 1-second response spectral acceleration data for 29 VA medical facilities reference site (Site Class B) conditions (USGS, 2008) factored by 1.3 to represent
1-second response spectral acceleration in the maximum horizontal direction.
VISN
No.
Return Period (years)
ID
No.
9,975
4,975
2,475
975
475
224
100
50
25
10
405
0.186
0.133
0.093
0.056
0.036
0.021
0.011
0.006
0.003
0.001
523
0.164
0.113
0.077
0.044
0.028
0.016
0.008
0.004
0.002
0.001
561
0.190
0.123
0.079
0.043
0.026
0.015
0.008
0.004
0.002
0.001
620
0.180
0.119
0.078
0.044
0.027
0.016
0.008
0.004
0.002
0.001
630
0.191
0.124
0.079
0.043
0.026
0.015
0.008
0.004
0.002
0.001
7
544
0.327
0.242
0.173
0.098
0.056
0.027
0.011
0.005
0.002
0.001
8
672
0.594
0.492
0.403
0.291
0.216
0.151
0.097
0.064
0.041
0.022
614
0.800
0.600
0.428
0.230
0.103
0.036
0.015
0.007
0.003
0.001
626
0.300
0.233
0.175
0.105
0.061
0.030
0.014
0.007
0.003
0.001
15
657A5
0.680
0.513
0.373
0.214
0.111
0.043
0.018
0.008
0.003
0.001
16
598A0
0.355
0.272
0.198
0.113
0.057
0.023
0.010
0.005
0.002
0.001
501
0.321
0.226
0.153
0.088
0.056
0.034
0.019
0.010
0.005
0.001
649
0.188
0.137
0.099
0.062
0.042
0.027
0.015
0.008
0.004
0.001
436
0.300
0.224
0.165
0.106
0.074
0.050
0.031
0.020
0.012
0.005
463
1.183
0.993
0.807
0.595
0.452
0.330
0.227
0.159
0.105
0.056
648
0.830
0.648
0.482
0.306
0.198
0.112
0.053
0.027
0.013
0.003
653
1.029
0.769
0.546
0.299
0.145
0.063
0.030
0.015
0.006
0.002
663
1.065
0.815
0.611
0.399
0.278
0.182
0.108
0.064
0.035
0.013
687
0.267
0.201
0.147
0.094
0.063
0.039
0.021
0.011
0.005
0.001
692
0.709
0.537
0.389
0.223
0.131
0.073
0.040
0.023
0.011
0.003
663A4
0.859
0.689
0.538
0.372
0.268
0.180
0.108
0.064
0.035
0.012
612
1.112
0.938
0.764
0.570
0.440
0.320
0.214
0.139
0.079
0.028
640
1.518
1.233
0.980
0.672
0.472
0.310
0.188
0.119
0.071
0.030
654
1.151
0.913
0.689
0.444
0.298
0.188
0.110
0.066
0.038
0.016
662
1.966
1.610
1.289
0.900
0.635
0.390
0.204
0.116
0.064
0.025
600
1.003
0.774
0.588
0.400
0.294
0.211
0.144
0.099
0.064
0.030
664
0.963
0.714
0.506
0.302
0.206
0.142
0.096
0.067
0.045
0.023
691A4
1.256
1.039
0.840
0.613
0.459
0.325
0.210
0.134
0.077
0.030
692
1.520
1.168
0.876
0.572
0.404
0.277
0.179
0.118
0.071
0.030
1
3
9
18
19
20
21
22
3-12
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 3-6. Example values of PGA, 0.3-second and 1-second response spectral acceleration and
corresponding site coefficients, respectively, for each of the 10 discrete levels of
probabilistic hazard used to calculate average annualized loss (Roseburg, Oregon, VA
facility site).
Ground Motion
Intensity Level
PGA and Spectral
Acceleration - Site Class B
Site Coefficient
(Site Class C)
PGA and Spectral
Acceleration - Site Class C
Number
GMi
R.P.
(yr.)
PGAi
(g)
SA03i
(g)
SA10i
(g)
Fai
Fvi
PGAi
(g)
SA03i
(g)
SA10i
(g)
1
9,975
0.886
1.744
1.029
1.00
1.30
0.886
1.744
1.338
2
4,975
0.655
1.307
0.769
1.00
1.30
0.655
1.307
0.999
3
2,475
0.459
0.935
0.546
1.04
1.30
0.477
0.973
0.710
4
975
0.249
0.522
0.299
1.20
1.52
0.299
0.626
0.455
5
475
0.125
0.263
0.145
1.20
1.66
0.150
0.316
0.241
6
224
0.054
0.120
0.063
1.20
1.70
0.065
0.144
0.106
7
100
0.028
0.062
0.030
1.20
1.70
0.034
0.074
0.051
8
50
0.016
0.034
0.015
1.20
1.70
0.019
0.041
0.026
9
25
0.008
0.016
0.006
1.20
1.70
0.009
0.020
0.011
10
10
0.002
0.001
0.002
1.20
1.70
0.003
0.001
0.003
Table 3-7. Example values of Kappa Index (degradation factor) for systems governed by 0.3second and 1-second response, respectively, for each of the 10 discrete levels of
probabilistic hazard used to calculate average annualized loss (Roseburg, Oregon, VA
facility site)
Ground Motion
Intensity Level
Systems (MBTs) Goverend by
0.3-second Spectral Response
Systems (MBTs) Goverend by
1-second Spectral Response
Number
GMi
Return
Period (yr)
Maximum
Mag (Mmax)
Minimum
Dist. (km)
Kappa
Index1
Maximum
Magnitude
Minimum
Dist. (km)
Kappa
Index1
1
9,975
NA
NA
6
NA
NA
6
2
4,975
NA
NA
6
NA
NA
6
3
2,475
NA
NA
6
NA
NA
6
4
975
NA
NA
6
NA
NA
6
5
475
NA
NA
6
NA
NA
6
6
224
NA
NA
6
NA
NA
6
7
100
NA
NA
6
NA
NA
6
8
50
NA
NA
6
NA
NA
6
9
25
NA
NA
6
NA
NA
6
10
10
NA
NA
6
NA
NA
6
1. Kappa Index based on maximum magnitude and minimum fault distance, when these data are available, or
VA Seismicity Index, when these data are not available, as defined in Table 4.7
3-13
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
CHAPTER 4. CAPACITY AND RESPONSE PARAMETERS
4.1
Response Calculation
Spectral Acceleration (g’s)
Peak response of the building is calculated from the intersection of the building capacity curve
and the demand spectrum of earthquake ground motions, as illustrated in Figure 4-1 for two
capacity curves and three example demand spectra. In this example, the three demand spectra
represent what can be considered as weak, medium and strong ground shaking, respectively, and
two building capacity curves represent weaker and stronger construction, respectively. As
shown in Figure 4-1, stronger and stiffer construction displaces less than weaker and more
flexible construction for the same level of spectral demand, and less damage is expected to the
structural system and nonstructural components sensitive to drift. In contrast, stronger
construction will shake at higher acceleration levels, and more damage is expected to
nonstructural components and contents sensitive to acceleration.
Demand
Spectra
Stronger, More Ductile Construction
Building Capacity Curves
Weaker, Less Ductile Construction
Weak
Shaking
Medium
Shaking
Strong
Shaking
Spectral Displacement (inches)
Figure 4.1. Example intersection of demand spectra and building capacity curves
The demand spectrum is 5%-damped spectrum of ground motions, as defined in Chapter 3,
reduced for effective damping greater than 5% damping. The amount of effective damping is a
function of the inherent elastic damping of the building type and additional energy dissipated
during inelastic response, considering possible degradation of the structure during repeated
cycles of inelastic response. Section 4.4 describes response methods and values of elastic
damping and inelastic response (degradation) parameters.
A building capacity curve is a plot of a building’s lateral load resistance as a function of a
characteristic lateral displacement (i.e., a force-deflection plot). It is derived from a plot of
static-equivalent base shear versus building displacement at the roof, known commonly as a
pushover curve. In order to facilitate direct comparison with spectral demand, base shear is
4-1
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
converted to spectral acceleration and the roof displacement is converted to spectral
displacement using modal properties that represent pushover response.
Pushover curves and related-capacity curves, are derived from nonlinear static analysis (NSA)
concepts similar to those of ASCE 41 (ASCE, 2006). Detailed (Tier 3) seismic evaluation
methods of ASCE 31 refer to FEMA 356 (now ASCE 41) for advanced analysis procedures
including NSA (pushover) procedures. When ASCE 31 building evaluations include a Tier 3
pushover analysis (which is not typical), results are used to determine the most reliable values of
building capacity curve parameters.
Spectral Acceleration (g’s)
Building capacity curves are constructed from values of the design coefficient, Cs, and other
capacity parameters as shown in Figure 4-2.
(Du, Au)
Ultimate Point:
Au = lAy
Du = lmDy
(Dy, Ay)
Yield Point:
Ay = Csg/a1
Dy = 9.8AyTe2
l
Cs = Design Value
Te = Building Period
g, l = Overstrength
m = Ductility
lm
Spectral Displacement (inches)
Figure 4-2. Example building capacity curve and control points.
The capacity curve is defined by two control points: (1) the “yield” capacity (Dy, Ay) control
point, and (2) the “ultimate” capacity (Du, Au) control point. The yield capacity represents the
lateral strength of the building and accounts for design strength, redundancies in design,
conservatism in code requirements and expected (rather than nominal) strength of materials.
Design strength, Cs, is based on seismic code provisions or on an estimate of lateral strength for
buildings not governed by earthquake loads. Certain buildings designed for wind, such as taller
buildings located in zones of low or moderate seismicity, may have lateral design strength
considerably greater than those based on seismic code provisions.
Capacity and response parameters, and the various building (and ground motion) data used to
determine these parameters are listed in Table 4-1 and described the following sections:
4-2
Seismic Risk Assessment of VA Hospital Buildings
Table 4-1.
Phase I Report- Approach and Methods
April 13, 2010
List of capacity and response parameters, and building and ground
motion data required for determination of values of these parameters.
Parameter
Name
Building or Ground Motion Data
Symbol
Description
Source
Capacity Parameters
Design Coefficient
Cs
Design Coefficient
Table 2-3
Elastic Period
Te
MBT
Number of Stories
SDL
Table 2-2
Table 2-2
Table 2-3
Overstrength (2)
g and l
MBT
Number of Stories
SDL
Significant Deficiencies (l)
Table 2-2
Table 2-2
Table 2-3
Tables 2-11a -c
Modal Response (2)
a1 and a2
MBT
Number of Stories
Table 2-2
Table 2-2
Ductility
m
Number of Stories
Table 2-2
Response Parameters
4.2
Elastic Damping
be
MBT
Table 2-2
Degradation
k
Magnitude (Mmax)
Fault Distance (df)
Chapter 3
Chapter 3
Values of Capacity Parameters
Capacity parameters include the design coefficient, Cs, the elastic period, Te, overstrength, g
and l, modal response, a1 and a2, and ductility, m, as described below.
Design Coefficient, Cs - The design coefficient, Cs, is one of building data of Table 2-3.
As discussed above, the value of design coefficient, Cs, is the larger of the seismic
coefficient used for building design or the effective normalized design strength of the
building considering wind and other loads. In those rare cases when building strength
(Au) is known from a pushover analysis, the value of Cs is back figured from Au.
Elastic Period, Te - Values of elastic period, Te, are given in Table 4-2
The effective period, Te, is a function of building height (number of above grade stories),
model building type and seismic design level, respectively. Values of elastic period
given in Table 4-1 are adapted from Table A6-3 of the OSHPD (SB 1953) regulations
and are the same as the default values of HAZUS (for model building types of the same
height) with the following exceptions.
4-3
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Values of elastic period are now limited to Te ≥ 0.25 seconds, consistent with the
fundamental period definition of Quantification of Building Seismic Performance
Factors, FEMA P695 (FEMA 2009), whereas HAZUS (and OSHPD regulations) have
slightly larger limits in the range of 0.35 - 0.40 seconds, depending on model building
type. In the same manner as HAZUS, values of elastic period follow the procedures of
Section 12.8.2 of ASCE 7, except that the value of upper-limit coefficient, Cu, now varies
from 1.4 to 1.7 as a function of the seismic design level in a manner consistent with Table
12.8-1 of ASCE 7, whereas HAZUS (and OSHPD regulations) assume Cu = 1.4 for all
levels of seismic design.
Note. While improvements, described above, make the values of the elastic period more
realistic, they are relatively modest changes and have small effect on risk calculations.
Overstrength Parameters, g and l - Values of overstrength parameters, g and l are given in Table
4-3
The values of overstrength parameters, g and l, are identical to those of Table A6-5 of
the OSHPD (SB 1953) regulations.
Modal Response Parameters, a1 and a2 - Values of modal response parameters, a1 and a2 are
given in Table 4-4
The values of modal response parameters, a1 and a2, are identical to those of Table A6-4
of the OSHPD (SB 1953) regulations.
Ductility Parameters, m - Values of the ductility parameter, m, are given in Table 4-5
The values of ductility parameter, m, are identical to those of Table A6-6 of the OSHPD
(SB 1953) regulations.
Note. The ductility parameter, m, is used to determine an appropriate displacement for
the ultimate control point of the capacity curve, Du, and is not intended to define the
system's displacement capacity (i.e., the "ultimate" control point represents the maximum
strength of the MBT of interest, not necessarily the maximum displacement).
4-4
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 4-2. Values of elastic period, Te, as a function of building height, model building type,
and seismic design level (adapted from Table A6-3, OSHPD, 2007)
Default Building Height, HR, and Elastic Period, Te, Properties
Structural System (MBT)
No. of
Stories
W1 and W2
(MH)
S1
C1
S2
Te
(sec.)
HR
(ft.)
Te
(sec.)
S4 and S5
C2, C3, PC2,
RM1, RM2,
URM
S3 and PC1
HR
(ft.)
Te
(sec.)
HR
(ft.)
Te
(sec.)
HR
(ft.)
Te
(sec.)
HR
(ft.)
Te
(sec.)
HR
(ft.)
Te
(sec.)
HR
(ft.)
1
14
0.25
14
0.32
12
0.25
14
0.29
14
0.25
12
0.25
15
0.27
2
24
0.38
24
0.50
20
0.33
24
0.43
24
0.33
20
0.28
25
0.39
3
34
0.49
36
0.69
30
0.48
36
0.59
36
0.44
30
0.39
35
0.50
4
44
0.60
48
0.87
40
0.62
48
0.73
48
0.55
40
0.48
5
54
0.70
High Code Seismic Design
60
1.04
50
0.76
60
0.86
60
0.65
50
0.57
6
72
1.20
60
0.89
72
0.99
72
0.74
60
0.65
7
84
1.36
70
1.03
84
1.11
84
0.84
70
0.73
8
96
1.51
80
1.16
96
1.22
96
0.92
80
0.81
9
108
1.66
90
1.29
108
1.34
108
1.01
90
0.88
10
120
1.81
100
1.41
120
1.45
120
1.09
100
0.95
11
132
1.95
110
1.54
132
1.55
132
1.17
110
1.02
12
144
2.09
120
1.67
144
1.66
144
1.25
120
1.09
13
156
2.23
130
1.79
156
1.76
156
1.33
130
1.16
14
168
2.36
140
1.91
168
1.86
168
1.40
140
1.23
15
180
2.50
150
2.04
180
1.96
180
1.48
150
1.29
16
192
2.63
160
2.16
192
2.06
192
1.55
160
1.35
17
204
2.76
170
2.28
204
2.15
204
1.62
170
1.42
18
216
2.89
180
2.40
216
2.25
216
1.70
180
1.48
19
228
3.02
190
2.52
228
2.34
228
1.77
190
1.54
>= 20
240
3.14
200
2.64
240
2.43
240
1.84
200
1.60
Moderate Code Seismic Design
1
14
0.27
14
0.35
12
0.25
14
0.31
14
0.25
12
0.25
15
0.29
2
24
0.41
24
0.53
20
0.36
24
0.46
24
0.35
20
0.31
25
0.42
3
34
0.53
36
0.74
30
0.51
36
0.63
36
0.47
30
0.41
35
0.54
4
44
0.64
48
0.93
40
0.66
48
0.78
48
0.59
40
0.51
5
54
0.75
60
1.11
50
0.81
60
0.92
60
0.70
50
0.61
6
72
1.29
60
0.96
72
1.06
72
0.80
60
0.70
7
84
1.45
70
1.10
84
1.19
84
0.89
70
0.78
8
96
1.62
80
1.24
96
1.31
96
0.99
80
0.86
9
108
1.78
90
1.38
108
1.43
108
1.08
90
0.94
10
120
1.93
100
1.51
120
1.55
120
1.17
100
1.02
11
132
2.09
110
1.65
132
1.66
132
1.26
110
1.10
12
144
2.24
120
1.78
144
1.78
144
1.34
120
1.17
13
156
2.39
130
1.92
156
1.89
156
1.42
130
1.24
14
168
2.53
140
2.05
168
1.99
168
1.50
140
1.31
15
180
2.68
150
2.18
180
2.10
180
1.58
150
1.38
16
192
2.82
160
2.31
192
2.21
192
1.66
160
1.45
17
204
2.96
170
2.44
204
2.31
204
1.74
170
1.52
18
216
3.10
180
2.57
216
2.41
216
1.82
180
1.58
19
228
3.23
190
2.70
228
2.51
228
1.89
190
1.65
>= 20
240
3.37
200
2.83
240
2.61
240
1.97
200
1.72
4-5
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 4-2. Values of elastic period, Te, as a function of building height, model building type,
and seismic design level (adapted from Table A6-3, OSHPD, 2007)
Default Building Height, HR, and Elastic Period, Te, Properties
Structural System (MBT)
No. of
Stories
W1 and W2
(MH)
S1
C1
S2
Te
(sec.)
HR
(ft.)
Te
(sec.)
S4 and S5
C2, C3, PC2,
RM1, RM2,
URM
S3 and PC1
HR
(ft.)
Te
(sec.)
HR
(ft.)
Te
(sec.)
HR
(ft.)
Te
(sec.)
HR
(ft.)
Te
(sec.)
HR
(ft.)
Te
(sec.)
HR
(ft.)
1
14
0.29
14
0.37
12
0.25
14
0.33
14
0.25
12
0.25
15
0.30
2
24
0.43
24
0.57
20
0.38
24
0.49
24
0.37
20
0.33
25
0.45
3
34
0.56
36
0.79
30
0.55
36
0.67
36
0.51
30
0.44
35
0.58
4
44
0.68
48
0.99
40
0.71
48
0.83
48
0.63
40
0.55
5
54
0.80
Low Code Seismic Design
60
1.19
50
0.87
60
0.98
60
0.74
50
0.65
6
72
1.37
60
1.02
72
1.13
72
0.85
60
0.74
7
84
1.55
70
1.17
84
1.27
84
0.95
70
0.83
8
96
1.73
80
1.32
96
1.40
96
1.06
80
0.92
9
108
1.90
90
1.47
108
1.53
108
1.15
90
1.01
10
120
2.06
100
1.62
120
1.65
120
1.25
100
1.09
11
132
2.23
110
1.76
132
1.78
132
1.34
110
1.17
12
144
2.39
120
1.90
144
1.90
144
1.43
120
1.25
13
156
2.55
130
2.05
156
2.01
156
1.52
130
1.32
14
168
2.70
140
2.19
168
2.13
168
1.61
140
1.40
15
180
2.85
150
2.33
180
2.24
180
1.69
150
1.47
16
192
3.01
160
2.47
192
2.35
192
1.77
160
1.55
17
204
3.15
170
2.60
204
2.46
204
1.86
170
1.62
18
216
3.30
180
2.74
216
2.57
216
1.94
180
1.69
19
228
3.45
190
2.88
228
2.68
228
2.02
190
1.76
>= 20
240
3.59
200
3.01
240
2.78
240
2.10
200
1.83
Pre-Code Seismic (Wind) Design
1
14
0.31
14
0.39
12
0.25
14
0.35
14
0.26
12
0.25
15
0.32
2
24
0.46
24
0.61
20
0.40
24
0.53
24
0.40
20
0.35
25
0.48
3
34
0.60
36
0.84
30
0.58
36
0.71
36
0.54
30
0.47
35
0.61
4
44
0.73
48
1.05
40
0.75
48
0.88
48
0.67
40
0.58
5
54
0.85
60
1.26
50
0.92
60
1.04
60
0.79
50
0.69
6
72
1.46
60
1.08
72
1.20
72
0.90
60
0.79
7
84
1.65
70
1.24
84
1.34
84
1.01
70
0.88
8
96
1.83
80
1.40
96
1.49
96
1.12
80
0.98
9
108
2.02
90
1.56
108
1.62
108
1.22
90
1.07
10
120
2.19
100
1.72
120
1.76
120
1.33
100
1.16
11
132
2.37
110
1.87
132
1.89
132
1.42
110
1.24
12
144
2.54
120
2.02
144
2.01
144
1.52
120
1.33
13
156
2.70
130
2.17
156
2.14
156
1.61
130
1.41
14
168
2.87
140
2.32
168
2.26
168
1.71
140
1.49
15
180
3.03
150
2.47
180
2.38
180
1.80
150
1.57
16
192
3.19
160
2.62
192
2.50
192
1.89
160
1.64
17
204
3.35
170
2.77
204
2.62
204
1.97
170
1.72
18
216
3.51
180
2.91
216
2.73
216
2.06
180
1.80
19
228
3.66
190
3.06
228
2.84
228
2.14
190
1.87
>= 20
240
3.82
200
3.20
240
2.95
240
2.23
200
1.94
4-6
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 4-3. Values of overstrength parameters, g and l, as a function of building
height, model building type, and performance (structural deficiencies)
adapted from Table A6-5, OSHPD, 2007)
Overstrength Factor (l)
No. of
Stories
Overstrength
Factor
W1, S1, C1
(g)
Structural System (MBT)
W2, C2
S4, C3
Other
PC1, URM
Baseline Performance
1
2.70
2.00
2.00
1.83
1.67
1.33
2
2.50
2.00
2.00
1.83
1.67
1.33
3
2.25
2.00
2.00
1.83
1.67
1.33
4
2.00
2.00
2.00
1.83
1.67
1.33
5
1.88
2.00
2.00
1.83
1.67
1.33
6
1.80
2.00
2.00
1.83
1.67
1.33
7
1.75
2.00
2.00
1.83
1.67
1.33
8
1.71
2.00
2.00
1.83
1.67
1.33
9
1.69
2.00
2.00
1.83
1.67
1.33
10
1.67
2.00
2.00
1.83
1.67
1.33
11
1.65
2.00
2.00
1.83
1.67
1.33
12
1.65
2.00
2.00
1.83
1.67
1.33
13
1.65
2.00
2.00
1.83
1.67
1.33
14
1.65
2.00
2.00
1.83
1.67
1.33
>= 15
1.65
2.00
2.00
1.83
1.67
1.33
No. of Stories
All
SubBase Performance
1.75
1.75
No. of Stories
All
1.63
1.50
1.25
1.33
1.17
USB Performance
1.50
1.50
1.42
4-7
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 4-4. Values of modal response parameters, a1 and a2, as a function of building
height and model building type, adapted from Table A6-4, OSHPD, 2007)
No. of
Stories
Modal Weight Factor, a1
Modal Height Factor, a2
Structural System (MBT)
Structural System (MBT)
S1 and C1
Other
Systems
PC1 and
URM
MH
MH
All Systems
(except MH)
0.75
0.8
0.75
1.00
1.00
0.75
2
0.75
0.8
0.75
0.75
3
0.75
0.8
0.75
0.75
4
0.75
0.8
0.75
5
0.75
0.8
0.75
6
0.73
0.79
0.72
7
0.71
0.78
0.69
8
0.69
0.77
0.66
9
0.67
0.76
0.63
10
0.65
0.75
0.60
11
0.65
0.75
0.60
12
0.65
0.75
0.60
13
0.65
0.75
0.60
14
0.65
0.75
0.60
>= 15
0.65
0.75
0.60
1
Table 4-5. Values of ductility, m, as a function of building
height, adapted from Table A6-6, OSHPD, 2007)
Number of Stories
Ductility Parameter, m
1
6.00
2
6.00
3
4.94
4
4.41
5
4.07
6
3.82
7
3.63
8
3.48
9
3.35
10
3.24
11
3.15
12
3.07
13
3.00
14
3.00
>= 15
3.00
4-8
Seismic Risk Assessment of VA Hospital Buildings
4.3
Phase I Report- Approach and Methods
April 13, 2010
Values of Response Parameters
The demand spectrum is calculated by reducing 5% damped response spectrum of earthquake
ground motions (Chapter 3) by factors, RA, in the acceleration domain and, RV, in the velocity
domain, as illustrated in Figure 4-3. As described previously, the intersection of the demand
spectrum and the capacity curve define the point of peak building response (D, A).
SS x FA
Spectral Acceleration (g’s)
5%-Damped Response Spectrum
(SS x FA)/RA
Demand Spectrum
Building Capacity Curve
A
(S1/T) x FV
((S1/T) x FV)/RV
Area
D
Spectral Displacement (inches)
Figure 4-3. Example calculation of demand spectrum by reduction of
5%-damped response spectrum of ground motions.
As described in Chapter 5 of the HAZUS TM, the reduction factors, RA and RV are a function of
total damping due to the combined effects of elastic damping, bE, and inelastic damping
associated with the non-degraded portion of area of the hysteresis loop shown in Figure 4-3. The
degradation factor, k, describes the non-degraded fraction of the area of the hysteresis loop.
These response parameters, bE and k, are described below.
Elastic Damping, bE - Values of the elastic damping parameter, bE, are given in Table 4-6
The values of elastic damping parameter, bE, are identical to those of Table A6-7 of the
OSHPD (SB 1953) regulations.
Degradation, k - Values of the degradation parameter, k, are given in Table 4-7
The values of degradation parameter, k, are identical to those of Table A6-8 of the
OSHPD (SB 1953) regulations, except for post-1975 and pre-1941 building for which
degradation factors now acknowledge less degradation for newer, post-1975 buildings,
and more degradation for older, pre-1941 buildings.
4-9
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 4-6. Values of the elastic damping factor, bE, adapted
from Table A6-7, OSHPD, 2007.
Structural System
(MBT)
Elastic Damping, β E
(% of Critical)
MH
5%
S1, S2, S3 and S4
5%
C1, C2, PC1 and PC2
7%
RM1 and RM2
7%
URM, C3 and S5
7%
W1 and W2
10%
Table 4.7. Values of the degradation parameter, k, as a function of ground motion parameters
(maximum magnitude and minimum fault rupture distance) or seismic design level,
and building age and performance (structural deficiencies), adapted from Table A6-8,
OSHPD, 2007.
Degradation Factor - k
Ground Motion Criteria
Scenario Earthquake
Baseline Performance - Building Age
Minimum
Distance
Site to
Fault1
(km)
Maximum
Magnitude,
Mmax2
<5
All
1
0.9
0.8
0.7
0.6
0.5
0.4
5 - 10
Mmax <= 6.5
2
0.9
0.8
0.7
0.6
0.5
0.4
5 - 10
Mmax > 6.5
3
0.8
0.7
0.6
0.5
0.4
0.3
10 - 25
Mmax <= 6.5
4
0.8
0.7
0.6
0.5
0.4
0.3
10 - 25
7.0 >=Mmax> 6.5
5
0.7
0.6
0.5
0.4
0.3
0.2
10 - 25
Mmax > 7.0
6
0.6
0.5
0.4
0.3
0.2
0.1
25 - 50
Mmax <= 7.0
7
0.6
0.5
0.4
0.3
0.2
0.1
25 - 50
Mmax > 7.0
MH
8
0.5
0.4
0.3
0.2
0.1
0.1
> 50
All
L, ML
9
0.5
0.4
0.3
0.2
0.1
0.1
Seismicity3
Kappa Post-1975 1960-1975 1941-1960 Pre-1941
Index, k
SubBase Performance - Building Age
Post-1975 1960-1975 1941-1960 Pre-1941
VH, H
1. Minimum distance to the fault that controls short-period ground motions (used to determine response of MBTs with Te < 0.8
Ts) or 1-second response (used to determine response of MBTs with Te > 0.8 Ts) at the building site.
2. Maximum magnitude (Mmax) of fault that controls short-period or 1-second ground motions at the building site
3. Use VA Seismicity Index (Table 1.1) when scenario properties unknown.
4-10
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
CHAPTER 5. BUILDING DAMAGE (FRAGILITY) PARAMETERS
5.1
Damage-State Probability
Building fragility curves are lognormal probability functions that describe the likelihood of
reaching, or exceeding, structural and nonstructural damage states, given an estimate of peak
building response (e.g., spectral displacement). These curves take into account the variability
and uncertainty associated with capacity curve properties, damage states and ground shaking.
Figure 5-1 provides an example of fragility curves for Slight. Moderate, Extensive and Complete
structural damage states, respectively, and illustrates differences in damage-state probabilities for
three levels of spectral response corresponding to weak, medium, and strong earthquake ground
shaking, respectively. The terms “weak,” “medium,” and “strong” are used here for simplicity;
in the actual methodology, only quantitative values of spectral response are used.
1.0
Probability
Slight
Moderate
Extensive
0.5
0.0
Complete
Weak
Shaking
Medium
Shaking
Strong
Shaking
Spectral Response
Figure 5-1. Example fragility curves for Slight, Moderate, Extensive and
Complete damage
The fragility curves distribute damage among Slight, Moderate, Extensive and Complete damage
states. For any given value of spectral response, discrete damage-state probabilities are
calculated as the difference of the cumulative probabilities of reaching, or exceeding successive
damage states. Discrete damage-state probabilities are used as inputs to the calculation of
various types of building-related loss.
Figure 5-2 shows an example of discrete damage state probabilities for weak, medium and strong
levels of earthquake ground shaking. The distribution of total probability (e.g., 1.0) between
damage states is calculated by the relative amount of probability at a given level of spectral
response (as illustrated by the vertical dashed lines in Figure 5-1).
5-1
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Probability
0.6
None
0.4
Slight
0.2
Moderate
0
Extensive
Complete
Weak
Shaking
Level
Med.
Strong
Damage
State
Figure 5-2. Example damage-state probabilities for weak, medium
and strong shaking levels.
Each fragility curve is defined by a median value of the demand parameter that corresponds to
the threshold of that damage state and by the total variability associated with that damage state.
The demand parameter is spectral displacement, Sd,ds, for the structure and drift-sensitive
nonstructural (NSD) components and spectral acceleration, Sa,ds, for acceleration-sensitive
nonstructural (NSA) components. The spectral displacement parameter, Sd,ds, is the product of
the story drift ratio, Dds, building height, HR, and modal parameter ratio, a2,/a3. Median values
of fragility curves are based on observations of damage in past earthquakes, laboratory tests of
structural components and systems, and engineering judgment. Table 6.3 of the HAZUS AEBM
summarizes median values of structural damage-states (in terms of story drift ratio) for each
model building type and seismic design level. Table 6.4 of the HAZUS AEBM summarizes
median values of NSD damage states (in terms of story drift ratio) and median values of NSA
damage states (in terms spectral acceleration, the latter as a function of seismic design level.
Lognormal standard deviation values, bds, describe the total variability of fragility-curve damage
states. Three primary sources contribute to the total variability of any given state, namely, the
variability associated with the capacity curve (bC), the variability associated with the demand
spectrum (bD), and the variability associated with threshold of the damage state (bT,ds).
Uncertainty due to damage-state threshold is assumed to be independent of other sources of
uncertainty. However, demand and capacity curve uncertainties are not independent (for the
structure and NSD components) and their combined affect on total damage-state variability is a
function of response, in particular post-yield response as characterized by the degradation factor,
k. Table 6.5 (low-rise buildings), Table 6.6 (mid-rise buildings) and Table 6.7 (high-rise
buildings) of the HAZUS AEBM provide values of total damage-state variability for the
structure, NSD components and NSA components, respectively, as a function of the degradation
factor (k), damage-state variability (bT,ds) and capacity curve variability (bC), respectively.
Fragility (damage-state probability) parameters, and the various building data used to determine
these parameters are listed in Table 5-1 and described the following sections:
5-2
Seismic Risk Assessment of VA Hospital Buildings
Table 5-1.
Phase I Report- Approach and Methods
April 13, 2010
List of fragility (damage-state probability) parameters for the structural
system, and nonstructural NSD and NSA components, respectively, and
building data required for determination of values of fragility parameters.
Parameter
Name
Building Data
Symbol
Description
Source
Structural System
Damage-State Median
(spectral displacement)
Sd,ds
Sd,ds = Dd,ds · HR · a2/a3
See below
Damage-State Median
(story drift ratio)
Dd,ds
MBT
SDL
Structural Deficiencies (Dd,ds)
Table 2-2
Table 2-2
Table 2-3
Building Height
HR
Building Height
Table 2-2
Modal Response (2)
a2 and a3
MBT
Number of Stories
Table 2-2
Table 2-2
Table 2-3
Structural Deficiencies (a3)
Damage-State Variability
bds
Number of Stories
Age
Structural Deficiencies (b d,ds)
Data Quality Rating
Table 2-2
Table 2-2
Table 2-3
Table 2-3
Nonstructural (NSD) Components
Damage-State Median
(spectral displacement)
Sd,ds
Sd,ds = Dd,ds · HR · a2/a3
See below
Damage-State Median
(story drift ratio)
Dd,ds
NSD Performance Rating
Table 2-3
Building Height
HR
Building Height
Table 2-2
Modal Response (2)
a2 and a3
MBT
Number of Stories
Struct. Deficiencies (a3, Dd,ds)
Table 2-2
Table 2-2
Table 2-3
Number of Stories
NSD Performance Rating
Data Quality Rating
Table 2-2
Table 2-3
Table 2-3
Damage-State Variability
bds
Nonstructural (NSA) Components or Contents (CON)
Damage-State Median
(spectral acceleration)
Sa,eff,ds
SDL
Performance Rating
Table 2-2
Table 2-3
Damage-State Variability
bds
Performance Rating
Data Quality Rating
Table 2-3
Table 2-3
Fraction of NSA at base
Fraction of CON at base
FNSA
FCON
No. of floors at/above grade
No. of floors below grade
Table 2-2
Table 2-2
5-3
Seismic Risk Assessment of VA Hospital Buildings
5.2
Phase I Report- Approach and Methods
April 13, 2010
Values of Structural Fragility Parameters
Structural fragility parameters include the median drift ratio, Dd,ds, building height, HR, modal
response, a3, and damage state variability, bT,ds, as described below, and the modal response
parameter, a2, previously described in Chapter 4.
Drift Ratio, Dd,ds - Values of the story drift ratio, Dd,ds, are given in Tables 5-3a - 5-3h, as defined
by mapping scheme of Table 5-2.
Table 5-2 is a matrix relating median values of damage states (story drift ratios) to
seismic design level (SDL) on one axis and structural performance (based on significant
deficiencies related to Dd,ds) on the other. Conceptually, median values of damage states
decrease (i.e., damage is more likely) with a decrease in the SDL and/or decrease in
performance.
The matrix of Table 5-2 defines median values of damage states in a systematic manner,
consistent (as possible) with the median damage-state values of the HAZUS AEBM and
the OSHPD (1953) regulations. Median Values of the story drift ratio, Dd,ds, are taken
from Table 6.3 of the HAZUS AEBM for Baseline performance. Median values of story
drift ratio for SubBase and USB performance are consistent with the Complete damage
story drift ratios of Tables A6-9 of the OSHPD (SB 1953) regulations, except for wood
frame buildings (W1/W2) which have slightly different values for consistency with
HAZUS AEBM values.
Building Height, HR - Building height is one of the building data of Table 2-3.
Modal Response Parameter, a3 - Values of the response parameter, a3, are given in Table 5-4
The values of a3, the ratio of maximum story drift to average story drift, are identical to
those of Table A6-10 of the OSHPD (SB 1953) regulations.
Lognormal Standard Deviation, bds - Values of the lognormal standard deviation, bds, are given
in Tables 5-5a - 5-5e as a function of building height, design vintage and structural
performance (based on significant deficiencies related to bds) for Best, Very Good, Good,
Poor and Very Poor quality ratings of building data, respectively.
Values of lognormal standard deviation (damage-state variability) given in Tables 5-5a 5-5e are based on "beta's" of Tables 6.5 - 6.7 of the HAZUS AEBM and correspond to
the contributing amounts of degradation (k), damage-state threshold variability (bT,ds) and
capacity curve variability (bC) shown at the bottom of each table. Damage-state
variability ranges from relatively small values associated with "Best" quality data for
post-1975 buildings with no significant deficiencies to relatively large values associated
with "Very Poor" quality data for pre-1941 buildings with significant deficiencies.
"Good" quality data would be typical of those provided with an ASCE 31 Tier 2 building
evaluation, and "Good" data values of Table 5-5c for 1960-1975 and 1941-1960
buildings are the same as those of Table A6-11 of the OSHPD (SB 1953) regulations.
5-4
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 5-2. Matrix mapping tables of median values of damage states (story drift ratios) to
seismic deign level and related structural deficiencies (performance rating).
Structural Performance Rating
SubBase
USB
Example Design Vintage
(UBC Zones 3/4)
Table 5-3a2
Table 5-3b
Table 5-3c
Post-1975 (I = 1.25)
1
Table 5-3c
Table 5-3e
Post-1975 (I = 1.0)
Seismic Design Level
1,2
Baseline
Special High Code
High Code
Moderate Code
Table 5-3b
Table 5-3c
1,3
3
Table 5-3d
Table 5-3f
3
1960 - 19753
Low Code
Table 5-3d1,4
Table 5-3e4
Table 5-3g4
1941 - 19604
Pre-Code (Wind)
Table 5-3e1
Table 5-3f
Table 5-3h
Pre-1941
1. Median values of structural damage (story drift ratio) for Baseline performance given in Tables 4.2b - 4.2e are based on Table
6.3 of the HAZUS AEBM Manual for High-Code. Moderate-Code, Low-Code and Pre-Code buildings, respectively (except W1/W2
buildings).
2. Median values of structural damage (story drift ratio) for Baseline performance given in Tables 5-3a are based on 1.25 x
values given in Matrix B for High-Code (post-1975) buildings, consistent with Chap. 6 of the HAZUS Technical Manual .
3. Median values of Complete structural damage (story drift ratio) given in Tables 5-3c, 5-3d, and 5-3f are consistent with Post-61
values of Table A6-9 of the OSHPD (SB 1953) regulations for Baseline, SubBase and USB performance, respectively (except
W1/W2 buildings).
4. Median values of Complete structural damage (story drift ratio) given in Tables 5-3d, 5-3e, and 5-3g are consistent with Pre-61
values of Table A6-9 of the OSHPD (SB 1953) regulations for Baseline, SubBase and USB performance, respectively (except
W1/W2 buildings).
Table 5-3a Values of median structural drift ratios as a function of model building type,
buildings with Baseline performance and Special High Code seismic design.
Model Building Type
Structural Damage State
Slight
Moderate
Extensive
Complete
W1, W2
0.005
0.015
0.050
0.125
S1
0.008
0.015
0.038
0.100
C1, S2
0.006
0.013
0.038
0.100
C2
0.005
0.013
0.038
0.100
S3, S4, PC1, PC2, RM1, RM2
0.005
0.010
0.030
0.088
S5, C3, URM
0.003
0.006
0.015
0.035
Table 5-3b Values of median structural drift ratios as a function of model building type,
buildings with Baseline performance and High Code seismic design.
Model Building Type
Structural Damage State
Slight
Moderate
Extensive
Complete
W1, W2
0.004
0.012
0.040
0.100
S1
0.006
0.012
0.030
0.080
C1, S2
0.005
0.010
0.030
0.080
C2
0.004
0.010
0.030
0.080
S3, S4, PC1, PC2, RM1, RM2
0.004
0.008
0.024
0.070
S5, C3, URM
0.003
0.006
0.015
0.035
5-5
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 5-3c Values of median structural drift ratios as a function of model building
type for buildings with Baseline performance and Moderate Code seismic
design (and SubBase performance/High Code design)
Model Building Type
Structural Damage State
Slight
Moderate
Extensive
Complete
W1, W2
0.004
0.010
0.031
0.075
S1
0.006
0.010
0.024
0.060
C1, S2
0.005
0.009
0.023
0.060
C2
0.004
0.008
0.023
0.060
S3, S4, PC1, PC2, RM1, RM2
0.004
0.007
0.019
0.053
S5, C3, URM
0.003
0.006
0.015
0.035
Table 5-3d Values of median structural drift ratios as a function of model building type
for buildings with Baseline performance and Low Code seismic design (and
SubBase performance/Moderate Code design)
Model Building Type
Structural Damage State
Slight
Moderate
Extensive
Complete
W1, W2
0.004
0.010
0.025
0.060
S1
0.006
0.010
0.020
0.050
C1, S2
0.005
0.008
0.020
0.050
C2
0.004
0.008
0.020
0.050
S3, S4, PC1, PC2, RM1, RM2
0.004
0.006
0.016
0.044
S5, C3, URM
0.003
0.006
0.015
0.035
Table 5-3e Values of median structural drift ratios as a function of model building
type for buildings with Baseline performance and Pre-Code seismic
design (and SubBase performance/Low Code design or USB
performance/High Code design )
Model Building Type
Structural Damage State
Slight
Moderate
Extensive
Complete
W1,W2
0.003
0.008
0.020
0.050
S1
0.005
0.008
0.016
0.040
C1, S2
0.004
0.006
0.016
0.040
C2
0.003
0.006
0.016
0.040
S3, S4, PC1, PC2, RM1, RM2
0.003
0.005
0.013
0.035
S5, C3, URM
0.002
0.005
0.012
0.028
5-6
Seismic Risk Assessment of VA Hospital Buildings
Table 5-3f
Phase I Report- Approach and Methods
April 13, 2010
Values of median structural drift ratios as a function of model building type
for buildings with SubBase performance and Pre-Code seismic design (and
USB performance/Moderate Code design )
Model Building Type
Structural Damage State
Slight
Moderate
Extensive
Complete
W1,W2
0.003
0.008
0.018
0.045
S1
0.005
0.008
0.012
0.030
C1, S2
0.004
0.006
0.012
0.030
C2
0.003
0.006
0.012
0.030
S3, S4, PC1, PC2, RM1, RM2
0.003
0.005
0.010
0.027
S5, C3, URM
0.002
0.005
0.008
0.018
Table 5-3g Values of median structural drift ratios as a function of model building type
for buildings with USB performance and Low Code seismic design
Model Building Type
Structural Damage State
Slight
Moderate
Extensive
Complete
W1,W2
0.003
0.008
0.015
0.038
S1
0.005
0.008
0.010
0.025
C1, S2
0.004
0.006
0.010
0.025
C2
0.003
0.006
0.010
0.025
S3, S4, PC1, PC2, RM1, RM2
0.003
0.005
0.008
0.022
S5, C3, URM
0.002
0.005
0.008
0.018
Table 5-3h Values of median structural drift ratios as a function of model building type
for buildings with USB performance and Pre-Code seismic design
Structural Damage State
Model Building Type
Slight
Moderate
Extensive
Complete
W1,W2
0.003
0.008
0.015
0.030
S1
0.005
0.008
0.010
0.020
C1, S2
0.004
0.006
0.010
0.020
C2
0.003
0.006
0.010
0.020
S3, S4, PC1, PC2, RM1, RM2
0.003
0.005
0.008
0.018
S5, C3, URM
0.002
0.005
0.008
0.014
5-7
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 5-4. Values of response parameter, a3, as a function of building height and related
structural deficiencies (performance), adapted from Table A6-10, OSHPD, 2007)
When Combined with Median Values of Structural Damage (Story Drift Ratios)
No. of
Stories
Baseline Story Drift Ratios
SubBase Story Drift Ratios
USB Story Drift Ratios
Structural Deficiencies (a3)
Structural Deficiencies (a3)
Structural Deficiencies (a3)
Baseline
SubBase
USB
Baseline
SubBase
USB
Baseline
SubBase
USB
1
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
1.00
2
1.21
1.62
2.03
1.21
1.62
2.03
1.21
1.62
2.03
3
1.35
2.04
2.73
1.35
2.04
2.73
1.35
2.04
2.50
4
1.45
2.36
3.27
1.45
2.36
3.27
1.45
2.36
2.50
5
1.54
2.63
3.72
1.54
2.63
3.72
1.54
2.50
2.50
6
1.62
2.87
4.11
1.62
2.87
4.00
1.62
2.50
2.50
7
1.69
3.07
4.46
1.69
3.07
4.00
1.69
2.50
2.50
8
1.75
3.26
4.77
1.75
3.26
4.00
1.75
2.50
2.50
9
1.81
3.43
5.00
1.81
3.43
4.00
1.81
2.50
2.50
10
1.86
3.59
5.00
1.86
3.59
4.00
1.86
2.50
2.50
11
1.91
3.73
5.00
1.91
3.73
4.00
1.91
2.50
2.50
12
1.96
3.87
5.00
1.96
3.87
4.00
1.96
2.50
2.50
13
2.00
4.00
5.00
2.00
4.00
4.00
2.00
2.50
2.50
14
2.04
4.12
5.00
2.04
4.00
4.00
2.04
2.50
2.50
>= 15
2.08
4.23
5.00
2.08
4.00
4.00
2.08
2.50
2.50
Table 5-5a. Values of lognormal standard deviation, bds, as a function of building height, design
vintage and related structural deficiencies (performance) for "Best" quality data.
Baseline Performance
SuβBase Performance
No. of
Stories
Post-1975
1960-1975
1941-1960
Pre-1941
Post-1975
1960-1975
1941-1960
Pre-1941
1
0.60
0.65
0.70
0.80
0.80
0.85
0.90
0.95
2
0.60
0.65
0.70
0.80
0.80
0.85
0.90
0.95
3
0.60
0.65
0.70
0.80
0.80
0.85
0.90
0.95
4
0.59
0.64
0.69
0.79
0.79
0.84
0.89
0.94
5
0.58
0.63
0.68
0.78
0.78
0.83
0.88
0.93
6
0.57
0.62
0.67
0.77
0.77
0.82
0.87
0.92
7
0.56
0.61
0.66
0.76
0.76
0.81
0.86
0.91
8
0.55
0.60
0.65
0.75
0.75
0.80
0.85
0.90
9
0.54
0.59
0.64
0.74
0.74
0.79
0.84
0.89
10
0.53
0.58
0.63
0.73
0.73
0.78
0.83
0.88
11
0.52
0.57
0.62
0.72
0.72
0.77
0.82
0.87
12
0.51
0.56
0.61
0.71
0.71
0.76
0.81
0.86
13
0.50
0.55
0.60
0.70
0.70
0.75
0.80
0.85
14
0.50
0.55
0.60
0.70
0.70
0.75
0.80
0.85
15
0.50
0.55
0.80
0.85
κ
βC
0.7-1.0
0.6-0.9
0.5-0.8
0.4-0.7
0.5-0.8
0.4-0.7
0.3-0.6
0.2-0.5
0.1
0.1
0.1
0.1
0.2
0.2
0.2
0.2
βT,ds
0.2
0.2
0.2
0.2
0.4
0.4
0.4
0.4
Factor
0.60
0.70
0.70
0.75
Approximate Value or Range of Contriβuting Factor
5-8
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 5-5b. Values of lognormal standard deviation, bds, as a function of building height, design
vintage and related structural deficiencies (performance) for "Very Good" quality data.
No. of
Stories
Baseline Performance
Post-1975
1960-1975
1941-1960
SuβBase Performance
Pre-1941
Post-1975
1960-1975
1941-1960
Pre-1941
1
0.70
0.75
0.80
0.85
0.85
0.90
0.95
1.00
2
0.70
0.75
0.80
0.85
0.85
0.90
0.95
1.00
3
0.70
0.75
0.80
0.85
0.85
0.90
0.95
1.00
4
0.69
0.74
0.79
0.84
0.84
0.89
0.94
0.99
5
0.68
0.73
0.78
0.83
0.83
0.88
0.93
0.98
6
0.67
0.72
0.77
0.82
0.82
0.87
0.92
0.97
7
0.66
0.71
0.76
0.81
0.81
0.86
0.91
0.96
8
0.65
0.70
0.75
0.80
0.80
0.85
0.90
0.95
9
0.64
0.69
0.74
0.79
0.79
0.84
0.89
0.94
10
0.63
0.68
0.73
0.78
0.78
0.83
0.88
0.93
11
0.62
0.67
0.72
0.77
0.77
0.82
0.87
0.92
12
0.61
0.66
0.71
0.76
0.76
0.81
0.86
0.91
13
0.60
0.65
0.70
0.75
0.75
0.80
0.85
0.90
14
0.60
0.65
0.70
0.75
0.75
0.80
0.85
0.90
15
0.60
0.65
0.85
0.90
κ
βC
0.6-0.9
0.5-0.8
0.4-0.7
0.3-0.6
0.5-0.8
0.4-0.7
0.3-0.6
0.2-0.5
0.15
0.15
0.15
0.15
0.25
0.25
0.25
0.25
βT,ds
0.25
0.25
0.25
0.25
0.45
0.45
0.45
0.45
Factor
0.70
0.75
0.75
0.80
Approximate Value or Range of Contriβuting Factor
Table 5-5c. Values of lognormal standard deviation, bds, as a function of building height, design
vintage and related structural deficiencies (performance) for "Good" quality data.
Baseline Performance
SuβBase Performance
No. of
Stories
Post-1975
1960-1975
1941-1960
Pre-1941
Post-1975
1960-1975
1941-1960
Pre-1941
1
0.80
0.85
0.90
0.95
0.90
0.95
1.00
1.05
2
0.80
0.85
0.90
0.95
0.90
0.95
1.00
1.05
3
0.80
0.85
0.90
0.95
0.90
0.95
1.00
1.05
4
0.79
0.84
0.89
0.94
0.89
0.94
0.99
1.04
5
0.78
0.83
0.88
0.93
0.88
0.93
0.98
1.03
6
0.77
0.82
0.87
0.92
0.87
0.92
0.97
1.02
7
0.76
0.81
0.86
0.91
0.86
0.91
0.96
1.01
8
0.75
0.80
0.85
0.90
0.85
0.90
0.95
1.00
9
0.74
0.79
0.84
0.89
0.84
0.89
0.94
0.99
10
0.73
0.78
0.83
0.88
0.83
0.88
0.93
0.98
11
0.72
0.77
0.82
0.87
0.82
0.87
0.92
0.97
12
0.71
0.76
0.81
0.86
0.81
0.86
0.91
0.96
13
0.70
0.75
0.80
0.85
0.80
0.85
0.90
0.95
14
0.70
0.75
0.80
0.85
0.80
0.85
0.90
0.95
15
0.70
0.75
0.90
0.95
κ
βC
0.5-0.8
0.4-0.7
0.3-0.6
0.2-0.5
0.4-0.7
0.3-0.6
0.2-0.5
0.1-0.4
0.2
0.2
0.2
0.2
0.3
0.3
0.3
0.3
βT,ds
0.3
0.3
0.3
0.3
0.5
0.5
0.5
0.5
Factor
0.80
0.85
0.80
0.85
Approximate Value or Range of Contriβuting Factor
5-9
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 5-5d. Values of lognormal standard deviation, bds, as a function of building height, design
vintage and related structural deficiencies (performance) for "Poor" quality data.
Baseline Performance
SuβBase Performance
No. of
Stories
Post-1975
1960-1975
1941-1960
Pre-1941
Post-1975
1960-1975
1941-1960
Pre-1941
1
0.90
0.95
1.00
1.05
0.95
1.00
1.05
1.10
2
0.90
0.95
1.00
1.05
0.95
1.00
1.05
1.10
3
0.90
0.95
1.00
1.05
0.95
1.00
1.05
1.10
4
0.89
0.94
0.99
1.04
0.94
0.99
1.04
1.09
5
0.88
0.93
0.98
1.03
0.93
0.98
1.03
1.08
6
0.87
0.92
0.97
1.02
0.92
0.97
1.02
1.07
7
0.86
0.91
0.96
1.01
0.91
0.96
1.01
1.06
8
0.85
0.90
0.95
1.00
0.90
0.95
1.00
1.05
9
0.84
0.89
0.94
0.99
0.89
0.94
0.99
1.04
10
0.83
0.88
0.93
0.98
0.88
0.93
0.98
1.03
11
0.82
0.87
0.92
0.97
0.87
0.92
0.97
1.02
12
0.81
0.86
0.91
0.96
0.86
0.91
0.96
1.01
13
0.80
0.85
0.90
0.95
0.85
0.90
0.95
1.00
14
0.80
0.85
0.90
0.95
0.85
0.90
0.95
1.00
15
0.80
0.85
0.95
1.00
κ
βC
0.4-0.7
0.3-0.6
0.2-0.5
0.1-0.4
0.4-0.7
0.3-0.6
0.2-0.5
0.1-0.4
0.3
0.3
0.3
0.3
0.35
0.35
0.35
0.35
βT,ds
0.5
0.5
0.5
0.5
0.55
0.55
0.55
0.55
Factor
0.90
0.95
0.85
0.90
Approximate Value or Range of Contriβuting Factor
Table 5-5e. Values of lognormal standard deviation, bds, as a function of building height, design
vintage and related structural deficiencies (performance) for "Very Poor" data.
Baseline Performance
SuβBase Performance
No. of
Stories
Post-1975
1960-1975
1941-1960
Pre-1941
Post-1975
1960-1975
1941-1960
Pre-1941
1
1.00
1.05
1.10
1.15
1.00
1.05
1.10
1.20
2
1.00
1.05
1.10
1.15
1.00
1.05
1.10
1.20
3
1.00
1.05
1.10
1.15
1.00
1.05
1.10
1.20
4
0.99
1.04
1.09
1.14
0.99
1.04
1.09
1.19
5
0.98
1.03
1.08
1.13
0.98
1.03
1.08
1.18
6
0.97
1.02
1.07
1.12
0.97
1.02
1.07
1.17
7
0.96
1.01
1.06
1.11
0.96
1.01
1.06
1.16
8
0.95
1.00
1.05
1.10
0.95
1.00
1.05
1.15
9
0.94
0.99
1.04
1.09
0.94
0.99
1.04
1.14
10
0.93
0.98
1.03
1.08
0.93
0.98
1.03
1.13
11
0.92
0.97
1.02
1.07
0.92
0.97
1.02
1.12
12
0.91
0.96
1.01
1.06
0.91
0.96
1.01
1.11
13
0.90
0.95
1.00
1.05
0.90
0.95
1.00
1.10
14
0.90
0.95
1.00
1.05
0.90
0.95
1.00
1.10
15
0.90
0.95
1.00
1.10
κ
βC
0.3-0.6
0.2-0.5
0.1-0.4
0.0-0.3
0.3-0.6
0.2-0.5
0.1-0.4
0.0-0.3
0.4
0.4
0.4
0.4
0.4
0.4
0.4
0.4
βT,ds
0.6
0.6
0.6
0.6
0.6
0.6
0.6
0.6
Factor
1.00
1.05
0.90
0.95
Approximate Value or Range of Contriβuting Factor
5-10
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
5.3
Values of Nonstructural and Contents Fragility Parameters and Methods
5.3.1
Nonstructural Drift-Sensitive (NSD) Components
Nonstructural drift-sensitive (NSD) component fragility parameters include the median story
drift ratio, Dd,ds, and lognormal standard deviation, bds, as described below, and building height,
HR, and modal response parameters, a2 and a2, as described in the previous section.
Story Drift Ratio, Dd,ds - Median values of the story drift ratio, Dd,ds, are given in Table 5-6.
Median values of story drift ratio, Dd,ds, given in Table 5-6 for Baseline performance are
the same as those of Table 6.4 of the HAZUS AEBM, and represent NSD components
that can accommodate approximately 2% story drift, in general.
Lognormal Standard Deviation, bds - Values of the lognormal standard deviation, bds, are given
in Table 5-7 as a function of building height, design vintage and general rating of NSD
performance and the quality rating of building data.
Values of lognormal standard deviation (damage-state variability) given in Tables 5-7 are
based on "beta's" of Tables 6.5 - 6.7 of the HAZUS AEBM and correspond to the
contributing amounts of degradation (k), damage-state threshold variability (bT,ds) and
capacity curve variability (bC) shown at the bottom of the table.
5.3.2
Modification of Spectral Acceleration - NSA Components and Contents
Damage to nonstructural acceleration-sensitive (NSA) components and contents located in upper
floors of the building is a function of peak floor acceleration estimated by the parameter, Sa, the
spectral acceleration associated with intersection of the building capacity curve and the demand
spectrum (i.e., "A" in Figure 4-3). Damage to NSA components and contents located at the first
floor or on floors below grade is a function of the peak ground acceleration, PGA. In some
cases, values of PGA and Sa are quite different, and amount of damage to NSA components and
contents located at upper floors is expected to be quite different from the amount of damage to
NSA components and contents located at the ground floor (or at floors below grade).
To account for potential differences in shaking intensity and related damage to NSA components
and contents located at upper floors and at (or below) the ground floor of the building, each
damage-state median, Sa,ds, is assumed to represent an effective spectral acceleration that is the
weighted combination of upper-floor and ground level acceleration, determined by the formulas
given in the following sections for NSA component damage and contents damage, respectively.
NSA Component Damage
The effective spectral acceleration, Sa,NSA, for evaluation of damage to NSA components is
calculated:
Sa , NSA = PGA FNSA + Sa (1 − FNSA )
5-11
(5-1)
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
where:
FNSA = (1 / 2 + N FBG ) /( N FBG + N FAG )
(5-2)
FNSA = fraction of NSA components at or below building base
PGA = peak ground acceleration (Chapter 3)
Sa =
peak floor acceleration (Chapter 4)
NFBG = number of floors below grade (Table 2-2)
NFAG = number of floors at or above grade (Table 2-2)
Contents Damage
The effective spectral acceleration, Sa,CON, for evaluation of damage to contents is calculated:
Sa ,CON = PGA FCON + Sa (1 − FCON )
(5-3)
FCON = (1 + N FBG ) /( N FBG + N FAG )
(5-4)
where:
FCON = fraction of contents at or below building base
PGA = peak ground acceleration (Chapter 3)
Sa =
peak floor acceleration (Chapter 4)
NFBG = number of floors below grade (Table 2-2)
NFAG = number of floors at or above grade (Table 2-2).
5.3.3
Nonstructural Acceleration-Sensitive (NSA) Components
Nonstructural acceleration-sensitive (NSA) component fragility parameters include median
values of spectral acceleration, Sa,ds, and lognormal standard deviation, bds, as described below.
Spectral Acceleration, Sa,ds - Median values of spectral acceleration, Sa,ds, are given in Table 5-8.
Median values of spectral acceleration, Sa,ds, given in Table 5-8 for Baseline performance
are the same as those of Table 6.4 of the HAZUS AEBM, and assume full anchorage and
bracing of NSA components.
Lognormal Standard Deviation, bds - Values of the lognormal standard deviation, bds, are given
in Tables 5-9 as a function of general rating of NSA performance and the quality rating of
building data.
Values of lognormal standard deviation (damage-state variability) given in Tables 5-9 are
based on "beta's" of Tables 6.5 - 6.7 of the HAZUS AEBM and correspond to the
contributing amounts of damage-state threshold variability (bT,ds) shown at the bottom of
the table.
5-12
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 5-6 Values of median drift ratios for NSD components as a function of the general
rating of NSD component performance.
Nonstructural (NSD) Component Damage State
Seismic Design Level
Slight
Moderate
Extensive
Complete
0.025
0.050
0.015
0.025
0.015
0.025
Baseline Seismic Performance1,2
0.004
All Design Levels
0.008
Poor Seismic Performance3
0.004
All Design Levels
0.008
3
Very Poor Performance
0.004
All Design Levels
0.008
1. Baseline median values taken from Table 6.4 HAZUS AEBM Manual
2. Baseline median values assume approximately 0.02 drift capacity of NSD components
3. Poor and Very Poor median values assume approximately 0.01, or less, drift capacity of NSD
components
Table 5-7. Values of lognormal standard deviation, bds, for NSD components as a function
of building height, related structural deficiencies (performance) and data quality.
Baseline Seismic Performance Rating
Poor/Very Poor Seismic Performance
Data Quality Rating
Data Quality Rating
No. of
Stories
Best
Very
Good
Good
Poor
Very
Poor
Best
Very
Good
Good
Poor
Very
Poor
1
0.65
0.75
0.85
0.95
1.05
0.85
0.90
0.95
1.00
1.05
2
0.65
0.75
0.85
0.95
1.05
0.85
0.90
0.95
1.00
1.05
3
0.65
0.75
0.85
0.95
1.05
0.85
0.90
0.95
1.00
1.05
4
0.64
0.74
0.84
0.94
1.04
0.84
0.89
0.94
0.99
1.04
5
0.63
0.73
0.83
0.93
1.03
0.83
0.88
0.93
0.98
1.03
6
0.62
0.72
0.82
0.92
1.02
0.82
0.87
0.92
0.97
1.02
7
0.61
0.71
0.81
0.91
1.01
0.81
0.86
0.91
0.96
1.01
8
0.60
0.70
0.80
0.90
1.00
0.80
0.85
0.90
0.95
1.00
9
0.59
0.69
0.79
0.89
0.99
0.79
0.84
0.89
0.94
0.99
10
0.58
0.68
0.78
0.88
0.98
0.78
0.83
0.88
0.93
0.98
11
0.57
0.67
0.77
0.87
0.97
0.77
0.82
0.87
0.92
0.97
12
0.56
0.66
0.76
0.86
0.96
0.76
0.81
0.86
0.91
0.96
13
0.55
0.65
0.75
0.85
0.95
0.75
0.80
0.85
0.90
0.95
14
0.55
0.65
0.75
0.85
0.95
0.75
0.80
0.85
0.90
0.95
15
0.55
0.65
0.75
0.85
0.95
0.75
0.80
0.85
0.90
0.95
Approximate Value or Range of Contriβuting Factor
Factor
κ
0.5-0.9
0.4-0.8
0.3-0.7
0.2-0.6
0.1-0.5
0.3-0.7
0.3-0.7
0.2-0.6
0.2-0.6
0.1-0.5
βC
0.10
0.15
0.20
0.30
0.40
0.20
0.25
0.30
0.35
0.40
βT,ds
0.20
0.25
0.40
0.50
0.60
0.40
0.45
0.50
0.55
0.60
5-13
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 5-8 Median values of spectral acceleration (units of g) for NSA components as a
function of the seismic design level and seismic performance rating of NSA
component.
Seismic Design Level
Nonstructural (NSA) Component Damage State
Slight
Moderate
Baseline Seismic Performance
0.45
0.9
Special High Code
Extensive
Complete
1.8
2.4
1,3
High Code
0.30
0.6
1.2
1.8
Moderate Code
0.25
0.5
1.0
1.5
Low Code
0.20
0.4
0.8
1.2
Pre-Code2
0.20
0.4
0.8
1.2
2
4
Special High Code
Poor Seismic Performance
0.30
0.6
1.2
1.8
High Code
0.25
1.0
1.5
0.5
Moderate Code
0.20
0.4
0.8
1.2
Low Code2
0.15
0.3
0.6
0.9
0.15
0.3
0.6
0.9
Pre-Code2
Very Poor Seismic Performance5
0.20
0.4
0.8
1.2
High Code
0.15
0.3
0.6
0.9
Moderate Code
0.15
0.3
0.6
0.9
Low Code
0.15
0.3
0.6
0.9
Pre-Code2
0.15
0.3
0.6
0.9
Special High Code
2
1. Baseline seismic performance median values taken from Table 6.4 HAZUS AEBM Manual
2. Median values for Low Code and Pre-Code assume no or minimal anchorage
3. Median values for Baseline seismic performance assume full anchorage of NSA components for forces
corresponding to the sesimc design level
4. Median values for Poor seismic performance assume partial anchorage of NSA components for forces
corresponding to the sesimc design level
5. Median values for Very Poor seismic performance assume no or minimal anchorage of NSA components
Table 5-9. Values of lognormal standard deviation, bds, for NSA components as a function
of related structural deficiencies (performance) and data quality rating.
Data Quality Rating
Variaβility
Best
Good
Very Good
Poor
Very Poor
Baseline Seismic Performance Rating
Total
0.35
0.43
0.50
0.58
0.65
βT,ds
0.2
0.3
0.4
0.5
0.6
Total
0.50
0.54
0.58
0.61
0.65
βT,ds
0.4
0.45
0.5
0.55
0.6
Total
0.65
0.65
0.65
0.65
0.65
βT,ds
0.6
0.6
0.6
0.6
0.6
Poor Seismic Performance Rating
Very Poor Seismic Performance Rating
5-14
Seismic Risk Assessment of VA Hospital Buildings
5.3.4
Phase I Report- Approach and Methods
April 13, 2010
Contents
Contents fragility parameters include median values of spectral acceleration, Sa,ds, and lognormal
standard deviation, bds, as described below.
Spectral Acceleration, Sa,ds - Median values of spectral acceleration, Sa,ds, are given in Table 510.
Median values of spectral acceleration, Sa,ds, given in Table 5-10 for Baseline
performance are based on values given in Table 6.4 of the HAZUS AEBM for NSA
components, and assume full anchorage and bracing of contents.
Lognormal Standard Deviation, bds - Values of the lognormal standard deviation, bds, are given
in Tables 5-11 as a function of general rating of contents seismic performance rating and
the quality rating of data.
Values of lognormal standard deviation (damage-state variability) given in Tables 5-11
are based on "beta's" of Tables 6.5 - 6.7 of the HAZUS AEBM for NSA components and
correspond to the contributing amounts of damage-state threshold variability (bT,ds)
shown at the bottom of the table.
5-15
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 5-10 Median values of spectral acceleration (units of g) for contents as a function of
the seismic design level and seismic performance rating of contents.
Seismic Design Level
Nonstructural (NSA) Component Damage State
Slight
Moderate
Baseline Seismic Performance
0.45
0.9
Special High Code
0.30
High Code
Extensive
Complete
1.8
2.4
1.2
1.8
1,3
0.6
Moderate Code
0.25
0.5
1.0
1.5
Low Code2
0.20
0.4
0.8
1.2
Pre-Code2
0.20
0.4
0.8
1.2
Special High Code
Poor Seismic Performance4
0.30
0.6
1.2
1.8
High Code
0.25
0.5
1.0
1.5
Moderate Code
0.20
0.4
0.8
1.2
Low Code
0.15
0.3
0.6
0.9
Pre-Code2
0.15
0.3
0.6
0.9
0.8
1.2
0.6
0.9
2
5
Very Poor Seismic Performance
0.20
0.4
Special High Code
0.15
High Code
0.3
0.15
0.3
0.6
0.9
Low Code
0.15
0.3
0.6
0.9
Pre-Code2
0.15
0.3
0.6
0.9
Moderate Code
2
1. Baseline seismic performance median values taken from Table 6.4 HAZUS AEBM Manual
2. Median values for Low Code and Pre-Code assume no or minimal anchorage
3. Median values for Baseline seismic performance assume full anchorage of NSA components for forces
corresponding to the sesimc design level
4. Median values for Poor seismic performance assume partial anchorage of NSA components for forces
corresponding to the sesimc design level
5. Median values for Very Poor seismic performance assume no or minimal anchorage of NSA components
Table 5-11. Values of lognormal standard deviation, bds, for contents as a function of
related structural deficiencies (performance) and data quality rating.
Data Quality Rating
Variaβility
Best
Good
Very Good
Poor
Very Poor
Baseline Seismic Performance Rating
Total
0.35
βT,ds
0.2
0.43
0.50
0.58
0.65
0.3
0.4
0.5
0.6
Poor Seismic Performance Rating
Total
0.50
βT,ds
0.4
0.54
0.58
0.61
0.65
0.45
0.5
0.55
0.6
Very Poor Seismic Performance Rating
Total
0.65
0.65
0.65
0.65
0.65
βT,ds
0.6
0.6
0.6
0.6
0.6
5-16
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
CHAPTER 6. LOSS PARAMETERS
6.1
Loss Calculation
Building loss calculation may be thought of as the second part of an integral two-step process
that transforms estimates of building damage (i.e., probability of damage state) into estimates of
various types of building loss. Building losses include casualties (deaths and injuries), loss of
function (downtime) and economic losses (cost to replace or repair damage). Although similar
in concept, methods used to transform building damage into loss vary somewhat depending on
the particular type of loss. Both expected values of losses and average annualized losses are
calculated.
6.1.1 Expected Value of Loss
The expected value of loss is estimated as the sum of losses from each damage state, where loss
associated with a given damage state is calculated by multiplying damage-state probability by a
loss ratio (or rate) and other factors that deterministically relate damage state to loss. For
example, the economic loss ratio for Complete structural damage, STRD5, is defined as 100
percent of the value of the structural system (i.e., complete economic loss) and loss due to
Complete damage would be 10 percent of value of the structural system if the probability of
Complete damage, PSTR5 = 0.10. Repeating this process for each structural damage state
(Slight, Moderate, Extensive and Complete) and summing the results provides a "point" estimate
of expected loss. This example may be expressed by the following equation (from Section 4.3.1
of the HAZUS AEBM):
5
EL _ STR = FVSTR RVB ∑ (PSTR ds STRD ds )
ds = 2
(6-1)
where:
EL_STR = expected economic loss due to repair/replacement of the structural
system.
PSTRds =
probability of structure being in damage state, ds
STRDds =
structural system repair cost of damage state, ds, expressed as a fraction
of the total cost of the structural system (loss ratio).
FVSTR =
fraction of total building replacement value, RVB, associated with the
structural system
RVB =
replacement value of building (dollars).
Equation (6-1) illustrates the types of data required to estimate losses: (1) building data (e.g.,
replacement value of building as described in Chapter 2), and (2) loss ratios or rates and related
factors (e.g., fraction of building value associated with the structural system) which are subject
of this chapter.
6-1
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Strictly speaking, the expected value is the mean of the distribution of the loss parameter of
interest and would necessarily involve incorporation of uncertainties associated with loss
rates/ratios which is not part of the HAZUS methodology. While the HAZUS methods provide
reasonable estimates of expected loss, they do not describe the uncertainty associated with the
loss parameter. That is, by how much could actual losses vary from the expected value?
While distributions of actual losses are not quantified, qualitative trends are known suggesting
that actual values of economic losses are likely within a factor of 2 from expected losses,
whereas actual number of casualties and amount of time associated with loss of function are
generally more uncertain. Casualties and downtime have greater uncertainty due to two primary
reasons. First, these losses tend to be dominated by one damage state, Complete structural
damage, which generally has a small and inherently more uncertain damage-state probability.
Second, casualty and, to some degree, functional loss rates are less well know than economic
loss rates (i.e., we have learned more from past earthquakes about dollar losses than about deaths
and downtime).
Fortunately, not knowing the distribution of loss does not preclude use of expected values of loss
to compare alternatives, or to rank buildings in terms of their relative risk. That is, buildings can
be effectively ranked using expected values of loss, recognizing that actual values of loss could
be different, but such differences should have a common bias (not affecting the ranking, in
general). Similarly, the type of earthquake ground motions (e.g., design earthquake or MCE
ground motions) also greatly influences expected losses, but should not affect the ranking, in
general, provided the same type of earthquake demand is used uniformly for risk assessment.
6.1.2
Average Annualized Loss
Expected values of loss, as described above, are conditional on the specific set of ground
motions used in the risk assessment. Thus, expected losses represent consequences of specific
scenario earthquake or are associated with a particular type or intensity of ground motions (e.g.,
10 percent loss given the building experiences design earthquake ground motions, etc.).
As an alternative and more pure measure of earthquake risk, losses can be estimated for all
possible levels of ground motion and combined based on the probability associated with each
level of ground motion. When such combinations are made using annual probability (or
frequency) of ground motion occurrence, the result is a distribution of annualized loss from
which an average mean value can be obtained, referred to as average annualized loss (AAL).
Site-dependent hazard functions (Chapter 3) provide values of annual probability of ground
motions as a function of building period.
For the VA-HAZUS study, estimates of AAL are made by combining discrete estimates of
expected loss (Section 6.1.1) for 10 different intensities of probabilistic ground motions, ranging
from very weak, likely ground motions to very strong, rare ground motions. Each of the 10
discrete sets of ground motions has an associated return period and an annual probability of
occurrence based on the range of return periods represented by that intensity of ground motions.
Table 6-1 summarizes the 10 ground motions and their respective annual probabilities of
occurrence.
6-2
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 6-1. Return periods and annual probabilities of ten sets of ground motions used to
calculate average annualized losses.
Discrete Ground Motion Intensity
Ground
Motion
GMi
Probability of Exceeding
Discrete Ground Motion Range
Return Period (years)
Return Period
(years)
Lower Bound Upper Bound
Annual
Probability
Pa[GMi]
50 Years
Annual
1
0.5%
1.00E-04
9,975
7,500
17,000
7.45E-05
2
1%
2.01E-04
4,975
3,500
7,500
1.52E-04
3
2%
4.04E-04
2,475
1,700
3,500
3.03E-04
4
5%
1.03E-03
975
750
1,700
7.45E-04
5
10%
2.11E-03
475
350
750
1.52E-03
6
20%
4.46E-03
224
170
350
3.03E-03
7
39%
1.00E-02
100
75
170
7.45E-03
8
63%
2.00E-02
50
35
75
1.52E-02
9
86%
4.00E-02
25
17
35
3.03E-02
10
99.3%
1.00E-01
10
7.5
17
7.45E-02
The process used to assess AAL is illustrated by the following formula which, in this case,
calculates AAL in terms of dollar loss to the structural system:
10
AAL _ STR = ∑ EL _ STR[GM i ] Pa [GM1 ]
i =1
(6-2)
where:
AAL_STR =
average annualized economic loss due to repair/replacement of the
structural system.
EL_STR[GMi] = expected value of economic loss due to repair/replacement of the
structural system for ground motion, GMi.
Pa[GMi] =
annual probability of ground motion, GMi.
Similar formulas calculate AAL for casualty and functional losses, respectively. As described in
Chapter 3, ground motions (GMi) are obtained from the most current hazard functions available
for the United States Geological Survey (USGS), adjusted as required for site conditions.
Expected values of loss used in Equation (6-2) are based on damage-state probabilities that
include spatial variability of ground motion demand (e.g., bD = 0.45 - 0.50). As such, the effect
on losses due ground motion variability is potentially "double counted" since the hazard
functions also incorporate ground motion uncertainty. However, potential double counting of
ground motion uncertainty would only apply to losses resulting from damage associated with
elastic or mildly inelastic response of the structure (e.g., Slight and Moderate states of structural
damage), and most losses tend to be dominated by the more severe states of damage (e.g.,
Extensive and Complete structural damage).Collapse evaluation methods of FEMA P695
[FEMA, 2009] show that a value of bD ≈ 0.4 is appropriate for systems responding inelastically.
6-3
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
The same caveats apply to AAL as discussed previously for expected losses, that is, not knowing
the distribution of (annualized) loss does not preclude use of AAL for comparison of
alternatives, or ranking of buildings. A potential benefit of using AAL, rather than expected
loss, to rank buildings would be the independence AAL on ground motion intensity. While
expected losses are necessarily conditional on the specific ground motion intensity selected for
risk assessment, AAL incorporates all intensities in the calculation on a consistent basis.
A potential pit fall of using AAL to assess risk is the inherent understating of earthquake effects.
Whereas expected losses are a "best estimate" of what will likely happen given the earthquake
ground motions used in the assessment actually occur, AAL essentially spreads the risk out
uniformly over time, diluting losses and masking consequences. For example, a risk assessment
of an acute care facility might find that that the expected number of beds lost is 100 (due to
severe building damage) for ground motions that occur ever 100 years, on average. On an
annualized basis this would only be 1 bed per year, on average. Is the risk of losing 100 beds
every 100 years the same as the risk of losing 1 bed per year? Risk assessments of VA hospital
buildings include both estimates of expected losses and AAL to provide these two different
perspective on earthquake risk.
6.2
Casualty Loss Parameters
The HAZUS technology classifies four levels of casualty severity, as defined in Table 6-2
Table 6-2. HAZUS Casualty Classification Scale (from Table 7.1 of the HAZUS AEBM)
Casualty Level
Casualty Description
Severity 1
Injuries requiring basic medical aid, but without hospitalization
(treat and release)
Severity 2
Injuries requiring medical attention and hospitalization, but not
considered to be life-threatening
Severity 3
Casualties that include entrapment and require expeditious rescue
and medical treatment to avoid death
Severity 4
Immediate deaths
HAZUS methods distinguish between “indoor” and “outdoor” casualties, the later referring to
deaths and injuries to pedestrians (or people in cars, etc.) that are near the building at the time of
the earthquake. Outdoor casualties are generally small relative to indoor casualties (e.g., due to
building collapse). The VA project follows the approach of the HAZUS AEBM and considers
only indoor casualties.
HAZUS methods base indoor casualty rates solely on structural damage states and base collapserelated deaths solely on Complete structural damage. Some buildings may have Collapse failure
of elements or components (e.g., out-of-plane failure of in-fill wall) prior to the building
reaching a Complete state of damage. Some buildings may also have nonstructural components
6-4
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
and equipment whose failure could cause injury and death of occupants. Additionally, casualties
due to fire, release of hazardous materials, electrocution or other indirect effects of structural or
nonstructural damage, are not explicitly included in casualty rates. For most buildings, these
effects do not dominate earthquake casualties. Structural damage tends to dominate deaths and
serious injuries, particularly when there is a significant probability of Complete damage.
Section 13.2 of the HAZUS AEBM describes the logic used to calculate casualties. The
calculations are complex, estimating casualties for each severity level due to each state of
structural damage, and for both Complete structural damage with collapse and without collapse,
as described by Equations (60-3a - 6-3c).
NS j = N O (S jNCOL + S jCOL )
(6-3a)

 5
S jNCOL =  ∑ P[S jNCOL | STRD i ] P[STRD i ]  (1 − P[COL | STRD 5 ] P[STRD 5 ])

 i=2
(6-3b)
S jCOL = P[S jCOL | COL] P[COL | STRD 5 ] P[STRD 5 ]
(6-3c)
where:
NSj =
NO =
SjNCOL =
number of building occupants in Casualty Severity j
number of building occupants, either NPO (Peak) or NECO (ECO)
fraction of building occupants in Casualty Severity j for all states of
structural damage other than Complete with collapse
SjCOL =
fraction of building occupants in Casualty Severity j for Complete
structural damage with building collapse
P[SjNCOL|STRDi] casualty rate for Severity j due to structural damage state i for
buildings without collapse (Tables 13.3 - 13.6 of the HAZUS TM)
P[SjCOL|STRDi] casualty rate for Severity j due to structural damage state i for
buildings with collapse (Table 13.7 of the HAZUS TM)
P[STRDi] =
probability of structural damage state i (see Chapter 5)
P[COL|STRD5] = collapse factor for buildings with Complete structural damage.
Casualty rates are a function of the type of structural system (MBT). Tables 13.3 through 13.6 of
the HAZUS TM define casualty rates, P[SjNCOL|STRDi], that specify Severity 1, Severity 2,
Severity 3 or Severity 4 casualties, respectively, as a function MBT and structural damage,
STRDi, assuming that the building has not collapsed. In general, these rates do not govern the
estimates of serious injuries and fatalities, which are primarily a function of building collapse.
Table 13.7 of the HAZUS TM defines casualty rates, P[SjCOL|STRDi], assuming some portion of
the building has collapsed, based on the product of the collapse factor, P[COL|STR5], times the
probability of Complete structural damage, P[STRD5]. The collapse factor may be thought of as
the effective fraction (or ratio) of the building that has collapsed such that when multiplied by
total building population the result is the likely number of building occupants exposed to lifethreatening collapse.
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Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Casualty losses are estimated for two building occupant conditions: (1) peak building occupancy
corresponding to maximum number of people in the buildings, day or night, and (2) effective
continuous occupancy (ECO) corresponding to the weighted average of building occupants
considering peak and off-time occupancy during after hours or weekend conditions Casualty
loss parameters, and the various building data used to determine these parameters are listed in
Table 6-1 and described in Section 6.2.1:
Table 6-3.
List of casualty loss parameters and building data required for
determination of values of casualty parameters.
Parameter
Name
Building Data
Symbol
Description
Source
Peak
ECO
Table 2-5
Table 2-5
Number of Building
Occupants
Casualty Rates w/o
Collapse (HAZUS)
P[SjNCOL|STRDds]
MBT
Table 2-2
Casualty Rates
w/Collapse (HAZUS)
P[SjCOL|COL]
MBT
Table 2-2
Collapse Rates
P[COL|STRD5]
MBT
Table 2-2
Table 6-4 provides values of the collapse factor, P[COL|STRD5], as function of structural
system, consistent with values of Table A6-12 of the OSHPD (SB 1953) regulations, and shows
deaths per 1,000 occupants in building with collapse for Baseline, SubB and USB performance.
Table 6-4. Values of the collapse factor, P[COL|STRD5], as a function of model building type
and related structural deficiencies, and example values of the number of Severity 4
casualties (immediate deaths) per 1,000 people given Complete structural damage.
Structural System
(Model Building Type)
Collapse Factor1
P[COL|STR5]
Structural Deficiencies
Severity 4
(Deaths)
per 1,000
given
Collapse2
Baseline
SubB
USB
W1
0.05
0.10
0.20
50
W2
0.05
0.10
0.20
100
S1, S2, S4 and S5
0.08
0.15
0.30
S3
0.08
0.15
C1, C2 and C3
0.13
PC1 and PC2
Severity 4 (Deaths) per 1,000 given
Complete Structural Damage3
Structural Deficiencies
Baseline
SubB
USB
2.5
5
10
5
10
20
100
8
15
30
0.30
50
4
8
15
0.25
0.50
100
13
25
50
0.15
0.30
0.60
100
15
30
60
RM1 and RM2
0.13
0.25
0.50
100
13
25
50
URM
0.15
0.30
0.60
100
15
30
60
1. From OSHPD Regulations Table A6-12, except URM based on PC1 rates.
2. From HAZUS TM Table 13.7.
3. Immediate Deaths (Severity Level 4) due to Complete structural damage with Collapse.
4. Casualty rates for injuries requiring hospitalization (Severity 2), and life-threatening injuries (Severity 3) and
corresponding theory are taken directly from HAZUS TM Chapter 13.
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Seismic Risk Assessment of VA Hospital Buildings
6.3
Phase I Report- Approach and Methods
April 13, 2010
Economic Loss Parameters
The HAZUS AEBM includes methods to calculate expected values of direct economic that
include costs of building repair (or replacement) of structural and nonstructural systems and
contents, as well as business interruption losses. Direct economic losses due to business
interruption are not included in VA risk assessments, although loss of function (downtime) is
included (see Section 6.4).
Repair cost rates define expected dollar costs (e.g., as fraction of building value) that would be
required to repair or replace building damage. Repair and replacement costs are required for
each state of damage of the structural system, nonstructural drift-sensitive components,
nonstructural acceleration-sensitive components and building contents. The value, and hence
repair and replacement costs, are different for each occupancy, and estimation of structural costs
is also different for each model building type. Table 2-6 (Inventory) defines the value per square
foot of different VA occupancies, and distribution of total cost between the structural,
nonstructural systems, and contents thereof, respectively.
HAZUS default values of direct economic loss for structural and nonstructural systems are based
on the following assumptions of the loss ratio corresponding to each state of damage:
•
Slight damage would be a loss of 2% of building’s replacement cost
•
Moderate damage would be a loss 10% of the building’s replacement cost
•
Extensive damage would be a loss of 50% of the building’s replacement cost
•
Complete damage would be a loss of 100% of the building’s replacement cost.
HAZUS assumes contents loss ratios to be one-half of the default loss ratios of the building on
the basis that one-half of building contents are not vulnerable to ground shaking and could be
salvaged even if the building were severely damaged. For VA risk assessment, the fractions
used to define HAZUS default costs of Slight, Moderate, Extensive and Complete damage are
assumed to be appropriate for buildings with limited structural deficiencies (global Baseline
performance).
Direct economic loss due to the repair (or replacement) of the structural system, nonstructural
drift-sensitive components, nonstructural acceleration-sensitive components and contents are
given by Equations (6-4), (6-5), (6-6) and (6-7), respectively:
5


EL _ STR = FVSTR RVB  (1 − P[COL]) ∑ (PSTR ds ∗ STRD ds ) + P[COL] 
ds = 2


(6-4)
5


EL _ NSD = FVNSD RVB  (1 − P[COL]) ∑ (PNSD ds ∗ NSDD ds ) + P[COL] 
ds = 2


(6-5)
5


EL _ NSA = FVNSA RVB  (1 − P[COL]) ∑ (PNSA ds ∗ NSAD ds ) + P[COL] 
ds = 2


(6-6)
6-7
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
5


EL _ CON = FVCON RVB  (1 − P[COL]) ∑ (PCON ds ∗ COND ds ) + P[COL] 
ds = 2


(6-7)
P[COL] = P[STRD 5 ] P[COL | STRD 5 ]
(6-8)
where:
EL_STR = loss due to repair of the structural system (dollars)
EL_NSD = loss due to repair of nonstructural drift-sensitive components (dollars)
EL_NSA = loss due to repair of nonstructural acceleration-sensitive components
(dollars)
EL_CON = loss due to repair (replacement) of contents (dollars)
PSTRds =
probability of structural damage state, ds
PNSDds =
probability of nonstructural drift-sensitive damage state, ds
PNSAds =
probability of nonstructural acceleration-sensitive damage state, ds
PCONds =
probability of contents damage state, ds
P[COL|STRD5]
collapse factor for buildings with Complete structural damage
STRDds =
structural system repair cost of damage state, ds, expressed as a fraction
of the total cost of the structural system (Table 6-5).
NSDDds =
nonstructural repair cost of damage state, ds, expressed as a fraction of
the total cost of nonstructural drift-sensitive components (Table 6-5).
NSADds =
nonstructural repair cost of damage state, ds, expressed as a fraction of
the total cost of nonstructural acceleration-sensitive components (Table
6-5)
CONDds =
contents repair cost of damage state, ds, expressed as a fraction of the
total cost of (acceleration-sensitive) contents (Table 6-5)
FVSTR =
fraction of total building replacement value, RVB, associated with the
structural system
FVNSD =
fraction of the fraction of total building replacement value, RVB,
associated with nonstructural drift-sensitive components (Table 2-6)
FVNSA =
fraction of the fraction of total building replacement value, RVB,
associated with nonstructural acceleration-sensitive components (Table
2-6)
FVCON =
fraction of the fraction of total building replacement value, RVB,
associated with (acceleration-sensitive) contents (Table 2-6)
RVB =
replacement value of building, dollars (Table 2-6).
Equations (6-4), (6-5), (6-6) and (6-7) are based on HAZUS theory but also incorporate the
probability of collapse, P[COL], in the calculation of expected losses. That is, these equations
recognize that building collapse would cause 100 percent loss of the affected portion of the
building, effectively trumping other possible states of damage. In most cases, the probability of
6-8
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
collapse is relatively small, and expected losses are not significantly affected. However,
probability of collapse can appreciably affect expected losses for buildings with collapse factors
based on SubB or USB performance, and evaluated using very strong ground motions. In
particular, expected values of contents loss can be appreciably affected by collapse that
effectively eliminates the chance of salvaging otherwise undamaged contents.
Table 6-5 provides values of the repair rates (as a fraction of the cost of the respective system for
each damage state) for the structure, nonstructural components and contents, respectively.
Repair rates are a function of overall (global) performance of the respective system. Repair rates
for Baseline performance (limited number of significant structural deficiencies) are consistent
with HAZUS default rates. Repair rates for Poor and Very Poor performance reflect higher costs
associated with more extensive repairs likely required for systems with a greater number of
significant deficiencies (e.g., not used to modify structure fragility).
Table 6-5. Repair cost of damage state, ds, expressed as a fraction of the total cost of the
structural system, nonstructural drift-sensitive (NSD) components,
nonstructural acceleration-sensitive (NSA) components, and contents,
respectively as a function of system performance (number of significant
deficiencies).
Damage State - Structural and Nonstrucutral Systems1
Occupancy
Slight
Moderate
Extensive
Complete
Baseline Seismic Performance (Deficiencies)1,2
All Occupancies
0.02
0.10
0.50
Poor Seismic Performance (Deficiencies)
All Occupancies
0.03
0.15
1.00
3
0.75
1.00
Very Poor Seismic Performance (Deficiencies)4
All Occupancies
0.04
0.20
1.00
1.00
Damage State - Contents2
Occupancy
Slight
Moderate
Extensive
Complete
Baseline Seismic Performance (Deficiencies)1,2
All Occupancies
0.01
0.05
0.25
Poor Seismic Performance (Deficiencies)
All Occupancies
0.015
0.075
0.38
Very Poor Seismic Performance (Deficiencies)
All Occupancies
0.02
0.10
0.50
3
0.50
0.50
4
0.50
1. HAZUS TM Section 15.2.1.1
2. HAZUS TM Table 15.6
3. Poor loss rates = 1.5 x Baseline rates, not to exceed Baseline Rate for Complete damage
3. Very Poor loss rates = 2.0 x Baseline rates, not to exceed Baseline rate for Complete damage
6-9
Seismic Risk Assessment of VA Hospital Buildings
6.4
Phase I Report- Approach and Methods
April 13, 2010
Functional Loss Parameters
Functional losses considered in VA risk assessments include (1) the expected number of days the
hospital building is assumed to be out of service (loss of function), and (2) the probability that
the building will not be operable as a function of time (days) following the earthquake. HAZUS
methods base loss of function on solely on damage to the structural system. For VA risk
assessments, functional losses consider damage to both structural and nonstructural systems.
Functional losses are calculated separately for structural and nonstructural systems, respectively.
Structural damage tends to govern loss of function for strong ground motions and long-term loss
of operability. Nonstructural damage tends to govern short-term loss of operation, particularly
for moderate ground motions that are not likely to cause Extensive or Complete structural
damage. The expected value of LOF is based on the more critical system. The probability of
LOF (as a function of says following the earthquake) is based on a statistical combination of
structural and nonstructural damage-state probabilities.
6.4.1
Expected Loss of Function due to Structural Damage
The HAZUS AEBM includes methods to calculate expected values of functional losses that
estimates of repair time, recovery time and loss of function (time). Repair time is the actual time
required to clean-up and repair (or replace) damaged elements (actual construction time).
Recovery time is the time required to fully recover operations, typically longer than actual repair
time due delays in decision making, financing, inspection, etc.. Loss of function (LOF) time is
the time that building operation or business will be interrupted, typically less than repair time for
lower states of damage that do not limit use of the building. LOF time is estimated as a fraction
of the recovery time (i.e., recovery time multiplied by service interruption time multiplier), the
time that the facility is not capable of conducting business and is typically less than repair time
due to temporary solutions, such as the use of alternative space, etc.
Expected loss of function, ELOFds, (in days) due to damage to the structure is calculated using
Equation (6-9):
5
ELOFSTR = ∑ (PSTR ds LOFds,STR )
(6-9)
ds = 2
where:
LOFds,STR = BCTds,STR MOD ds,STR
(6-10)
ELOFSTR =
expected loss of function, in days, due to damage to the structure.
LOFds,STR =
loss of function (in days) for structural damage state, ds.
PSTRds =
probability of building being in structural damage state, ds
BCTds,STR =
building recovery time (in days) for structural damage state, ds.
MODds,STR = service interruption time multiplier for structural damage state, ds.
6-10
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Functional loss parameters are a function of facility use (occupancy) and, similar to direct
economic losses, are also a function of seismic performance rating of the structural system.
Tables 6-6a, 6-6b and 6-6c provide values of the recovery time, BCTds,STR, and the service
interruption time multiplier. MODds,STR, as a function of structural damage state and building
occupancy for Baseline, Poor and Very Poor performance, respectively.
Functional loss parameters for Baseline performance (limited number of significant structural
deficiencies) are consistent with HAZUS default rates. Functional loss parameters for Poor and
Very Poor performance reflect LOF times associated with more extensive repairs likely required
for systems with a greater number of significant deficiencies (e.g., not used to modify structure
fragility).
6.4.2
Expected Loss of Function due to Nonstructural Damage
Nonstructural damage is known to influence operability of hospitals immediately following an
earthquake, and VA risk assessments consider functional losses due to nonstructural damage as
well as structural damage. Nonstructural methods are the same as the structural methods
described in Section 6.4.1, except that values of the recovery time, BCTds,NSA, and the service
interruption time multiplier. MODds,NSA, are based on damage to nonstructural accelerationsensitive (NSA) components. For convenience, functional losses are based on damage to NSA
components only, since NSA components tend to be more critical to building function, and
explicitly consideration of NSD would not appreciably affect losses.
Expected loss of function, ELOFds, (in days) due to damage to nonstructural components is
calculated using Equation (6-11):
5
ELOFNSA = ∑ (PNSA ds LOFds, NSA )
(6-11)
LOFds, NSA = BCTds, NSA MOD ds, NSA
(6-12)
ds = 2
where:
ELOFNSA =
expected loss of function, in days, due to nonstructural damage.
LOFds,NSA = loss of function (in days), NSA component damage state, ds.
PNSAds =
probability of building being in NSA component damage state, ds
BCTds,NSA = building recovery time (in days), NSA component damage state, ds.
MODds,NSA = service interruption time multiplier, NSA component damage state, ds.
Functional loss parameters are a function of facility use (occupancy) and the seismic
performance rating of NSA components. Tables 6-7a, 6-7b and 6-7c provide values of the
recovery time, BCTds,NSA, and the service interruption time multiplier. MODds,NSA, as a function
of structural damage state and building occupancy for Baseline, Poor and Very Poor
performance, respectively. Functional loss parameters for Poor and Very Poor performance
reflect LOF times associated with more extensive repairs likely required for systems with a
greater number of significant deficiencies (e.g., not used to modify structure fragility).
6-11
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Tables 6-6a. Values of recovery time, BCTds,STR, and service interruption time multiplier,
MODds,STR, as a function of structural damage state and building occupancy for
Baseline seismic performance of the structure (structural deficiencies).
Recovery Time1 (days)
Structural Damage State
Occupancy Class
Building Use
at VA Facility
HAZUS
Service Interruption Time Multipliers2
Structural Damage State
Slight
Moderate
Extensive
Complete
Slight
Moderate
Extensive
Complete
Dormitory
RES5
10
90
360
480
0.0
0.5
1.0
1.0
Domiliciliaries
RES6
10
120
480
960
0.0
0.1
0.2
0.3
Retail Trade
COM1
10
90
270
360
0.0
0.1
0.3
0.4
Wharehouse (Storage)
COM2
10
90
270
360
0.0
0.2
0.3
0.4
Maintenance Shops
COM3
10
90
270
360
0.0
0.2
0.3
0.4
Administrative (Offices)
COM4
20
90
360
480
0.0
0.1
0.2
0.3
Banks
COM5
20
90
180
360
0.0
0.1
0.2
0.3
Accute Care
COM6
20
135
540
720
0.0
0.1
0.2
0.3
COM6A
20
135
540
720
0.0
0.1
0.2
0.3
COM7
20
135
270
540
0.0
0.1
0.2
0.3
COM7A
20
135
270
540
0.0
0.1
0.2
0.3
Recreational
COM8
20
90
180
360
0.0
1.0
1.0
1.0
Auditorium
COM9
20
90
180
360
0.0
1.0
1.0
1.0
Parking
COM10
5
60
180
360
0.0
1.0
1.0
1.0
Boiler Plant
IND2
10
90
240
360
0.0
0.2
0.3
0.4
Post Office
GOV1
10
90
360
480
0.0
0.1
0.2
0.3
Fire, Police, EOC, Comm.
GOV2
10
60
270
360
0.0
0.1
0.2
0.3
Training
EDU1
10
90
360
480
0.0
0.1
0.2
0.3
Long-Term Care
Clinical (Outpatient)
Medical Research
1. HAZUS TM Table 15.11
2. HAZUS TM Table 15.12 (except RES6/COM5/COM6/COM7/GOV1/GOV2/EDU1 set equal to COM4, Slight set equal to 0.0, all)
Tables 6-6b. Values of recovery time, BCTds,STR, and service interruption time multiplier,
MODds,STR, as a function of structural damage state and building occupancy for
Poor seismic performance rating of the structure (structural deficiencies).
Recovery Time1 (days)
Structural Damage State
Occupancy Class
Building Use
at VA Facility
HAZUS
Service Interruption Time Multipliers2
Structural Damage State
Slight
Moderate
Extensive
Complete
Slight
Moderate
Extensive
Complete
Dormitory
RES5
15
135
480
480
0.0
0.5
1.0
1.0
Domiliciliaries
RES6
15
180
720
960
0.0
0.1
0.2
0.3
Retail Trade
COM1
15
135
360
360
0.0
0.1
0.3
0.4
Wharehouse (Storage)
COM2
15
135
360
360
0.0
0.2
0.3
0.4
Maintenance Shops
COM3
15
135
360
360
0.0
0.2
0.3
0.4
Administrative (Offices)
COM4
30
135
480
480
0.0
0.1
0.2
0.3
Banks
COM5
30
135
270
360
0.0
0.1
0.2
0.3
Accute Care
COM6
30
203
720
720
0.0
0.1
0.2
0.3
COM6A
30
203
720
720
0.0
0.1
0.2
0.3
COM7
30
203
405
540
0.0
0.1
0.2
0.3
COM7A
30
203
405
540
0.0
0.1
0.2
0.3
Recreational
COM8
30
135
270
360
0.0
1.0
1.0
1.0
Auditorium
COM9
30
135
270
360
0.0
1.0
1.0
1.0
Parking
COM10
8
90
270
360
0.0
1.0
1.0
1.0
Boiler Plant
IND2
15
135
360
360
0.0
0.2
0.3
0.4
Post Office
GOV1
15
135
480
480
0.0
0.1
0.2
0.3
Fire, Police, EOC, Comm.
GOV2
15
90
360
360
0.0
0.1
0.2
0.3
Training
EDU1
15
135
480
480
0.0
0.1
0.2
0.3
Long-Term Care
Clinical (Outpatient)
Medical Research
1. HAZUS TM Table 15.11
2. HAZUS TM Table 15.12 (except RES6/COM5/COM6/COM7/GOV1/GOV2/EDU1 set equal to COM4, Slight set equal to 0.0, all)
3. Poor Recovery Time = 1.5 x Baseline Recovery Time, not to exceed Baseline Recovery Time for Complete damage
6-12
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Tables 6-6c. Values of recovery time, BCTds,STR, and service interruption time multiplier,
MODds,STR, as a function of structural damage state and building occupancy for
Very Poor seismic performance rating of the structure (structural deficiencies).
Recovery Time1 (days)
Structural Damage State
Occupancy Class
Building Use
at VA Facility
HAZUS
Service Interruption Time Multipliers2
Structural Damage State
Slight
Moderate
Extensive
Complete
Slight
Moderate
Extensive
Complete
Dormitory
RES5
20
180
480
480
0.0
0.5
1.0
1.0
Domiliciliaries
RES6
20
240
960
960
0.0
0.1
0.2
0.3
Retail Trade
COM1
20
180
360
360
0.0
0.1
0.3
0.4
Wharehouse (Storage)
COM2
20
180
360
360
0.0
0.2
0.3
0.4
Maintenance Shops
COM3
20
180
360
360
0.0
0.2
0.3
0.4
Administrative (Offices)
COM4
40
180
480
480
0.0
0.1
0.2
0.3
Banks
COM5
40
180
360
360
0.0
0.1
0.2
0.3
Accute Care
COM6
40
270
720
720
0.0
0.1
0.2
0.3
COM6A
40
270
720
720
0.0
0.1
0.2
0.3
COM7
40
270
540
540
0.0
0.1
0.2
0.3
COM7A
40
270
540
540
0.0
0.1
0.2
0.3
Recreational
COM8
40
180
360
360
0.0
1.0
1.0
1.0
Auditorium
COM9
40
180
360
360
0.0
1.0
1.0
1.0
Parking
COM10
10
120
360
360
0.0
1.0
1.0
1.0
Boiler Plant
IND2
20
180
360
360
0.0
0.2
0.3
0.4
Post Office
GOV1
20
180
480
480
0.0
0.1
0.2
0.3
Fire, Police, EOC, Comm.
GOV2
20
120
360
360
0.0
0.1
0.2
0.3
Training
EDU1
20
180
480
480
0.0
0.1
0.2
0.3
Long-Term Care
Clinical (Outpatient)
Medical Research
1. HAZUS TM Table 15.11
2. HAZUS TM Table 15.12 (except RES6/COM5/COM6/COM7/GOV1/GOV2/EDU1 set equal to COM4, Slight set equal to 0.0, all)
3. Very Poor Recovery Time = 2.0 x Baseline Recovery Time, not to exceed Baseline Recovery Time for Complete damage
Tables 6-7a. Values of recovery time, BCTds,NSA, and service interruption time multiplier,
MODds,NSA, as a function of NSA Component damage state and building occupancy
for Baseline seismic performance of NSA Components (NSA deficiencies).
Recovery Time1 (days)
Structural Damage State
Occupancy Class
Building Use
at VA Facility
HAZUS
Service Interruption Time Multipliers2
Structural Damage State
Slight
Moderate
Extensive
Complete
Slight
Moderate
Extensive
Complete
Dormitory
RES5
10
90
180
180
0.1
0.5
1.0
1.0
Domiliciliaries
RES6
10
120
240
240
0.1
0.1
0.2
0.3
Retail Trade
COM1
10
90
180
180
0.1
0.1
0.3
0.4
Wharehouse (Storage)
COM2
10
90
180
180
0.1
0.2
0.3
0.4
Maintenance Shops
COM3
10
90
180
180
0.1
0.2
0.3
0.4
Administrative (Offices)
COM4
20
90
180
180
0.1
0.1
0.2
0.3
Banks
COM5
20
90
180
180
0.1
0.1
0.2
0.3
Accute Care
COM6
20
135
270
270
0.1
0.1
0.2
0.3
COM6A
20
135
270
270
0.1
0.1
0.2
0.3
COM7
20
135
270
270
0.1
0.1
0.2
0.3
COM7A
20
135
270
270
0.1
0.1
0.2
0.3
COM8
20
90
180
180
0.1
1.0
1.0
1.0
Auditorium
COM9
20
90
180
180
0.1
1.0
1.0
1.0
Parking
COM10
5
60
120
120
0.1
1.0
1.0
1.0
Boiler Plant
IND2
10
90
180
180
0.1
0.2
0.3
0.4
Post Office
GOV1
10
90
180
180
0.1
0.1
0.2
0.3
Fire, Police, EOC, Comm.
GOV2
10
60
120
120
0.1
0.1
0.2
0.3
Training
EDU1
10
90
180
180
0.1
0.1
0.2
0.3
Long-Term Care
Clinical (Outpatient)
Medical Research
Recreational
1. Based on Table 6.6a, except recovery time for Extensive/Complete based on 2.0 x Moderate damage values
2. Based on Table 6.6a, except Slight set equal to 0.1 for all occupancies (similar to HAZUS TM 15.12)
6-13
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Tables 6-7b. Values of recovery time, BCTds,NSA, and service interruption time multiplier,
MODds,NSA, as a function of NSA component damage state and building occupancy
for Poor seismic performance rating of NSA components (NSA deficiencies).
Recovery Time1 (days)
Structural Damage State
Occupancy Class
Building Use
at VA Facility
HAZUS
Service Interruption Time Multipliers2
Structural Damage State
Slight
Moderate
Extensive
Complete
Slight
Moderate
Extensive
Complete
Dormitory
RES5
15
135
180
180
0.1
0.5
1.0
1.0
Domiliciliaries
RES6
15
180
240
240
0.1
0.1
0.2
0.3
Retail Trade
COM1
15
135
180
180
0.1
0.1
0.3
0.4
Wharehouse (Storage)
COM2
15
135
180
180
0.1
0.2
0.3
0.4
Maintenance Shops
COM3
15
135
180
180
0.1
0.2
0.3
0.4
Administrative (Offices)
COM4
30
135
180
180
0.1
0.1
0.2
0.3
Banks
COM5
30
135
180
180
0.1
0.1
0.2
0.3
Accute Care
COM6
30
203
270
270
0.1
0.1
0.2
0.3
COM6A
30
203
270
270
0.1
0.1
0.2
0.3
COM7
30
203
270
270
0.1
0.1
0.2
0.3
COM7A
30
203
270
270
0.1
0.1
0.2
0.3
Recreational
COM8
30
135
180
180
0.1
1.0
1.0
1.0
Auditorium
COM9
30
135
180
180
0.1
1.0
1.0
1.0
Parking
COM10
8
90
120
120
0.1
1.0
1.0
1.0
Boiler Plant
IND2
15
135
180
180
0.1
0.2
0.3
0.4
Post Office
GOV1
15
135
180
180
0.1
0.1
0.2
0.3
Fire, Police, EOC, Comm.
GOV2
15
90
120
120
0.1
0.1
0.2
0.3
Training
EDU1
15
135
180
180
0.1
0.1
0.2
0.3
Long-Term Care
Clinical (Outpatient)
Medical Research
1. Based on Table 6.7a, except recovery time for Slight/Moderate based on 1.5 x Baseline values
2. Based on Table 6.6a, except Slight set equal to 0.1 for all occupancies (similar to HAZUS TM 15.12)
Tables 6-7c. Values of recovery time, BCTds,NSA, and service interruption time multiplier,
MODds,NSA, as a function of structural damage state and building occupancy for
Very Poor seismic performance rating of the structure (structural deficiencies).
Recovery Time1 (days)
Structural Damage State
Occupancy Class
Building Use
at VA Facility
HAZUS
Service Interruption Time Multipliers2
Structural Damage State
Slight
Moderate
Extensive
Complete
Slight
Moderate
Extensive
Complete
Dormitory
RES5
20
180
180
180
0.1
0.5
1.0
1.0
Domiliciliaries
RES6
20
240
240
240
0.1
0.1
0.2
0.3
Retail Trade
COM1
20
180
180
180
0.1
0.1
0.3
0.4
Wharehouse (Storage)
COM2
20
180
180
180
0.1
0.2
0.3
0.4
Maintenance Shops
COM3
20
180
180
180
0.1
0.2
0.3
0.4
Administrative (Offices)
COM4
40
180
180
180
0.1
0.1
0.2
0.3
Banks
COM5
40
180
180
180
0.1
0.1
0.2
0.3
Accute Care
COM6
40
270
270
270
0.1
0.1
0.2
0.3
COM6A
40
270
270
270
0.1
0.1
0.2
0.3
Long-Term Care
COM7
40
270
270
270
0.1
0.1
0.2
0.3
COM7A
40
270
270
270
0.1
0.1
0.2
0.3
Recreational
COM8
40
180
180
180
0.1
1.0
1.0
1.0
Auditorium
COM9
40
180
180
180
0.1
1.0
1.0
1.0
Parking
Clinical (Outpatient)
Medical Research
COM10
10
120
120
120
0.1
1.0
1.0
1.0
Boiler Plant
IND2
20
180
180
180
0.1
0.2
0.3
0.4
Post Office
GOV1
20
180
180
180
0.1
0.1
0.2
0.3
Fire, Police, EOC, Comm.
GOV2
20
120
120
120
0.1
0.1
0.2
0.3
Training
EDU1
20
180
180
180
0.1
0.1
0.2
0.3
1. Based on Table 6.7a, except recovery time for Slight/Moderate based on 2.0 x Baseline values
2. Based on Table 6.6a, except Slight set equal to 0.1 for all occupancies (similar to HAZUS TM 15.12)
6-14
Seismic Risk Assessment of VA Hospital Buildings
6.4.3
Phase I Report- Approach and Methods
April 13, 2010
Probability of Loss of Function
The likelihood that a building sustains loss of function (LOF) due to structural or nonstructural
damage will be the greatest immediately following the earthquake and decease with time as
temporary solutions are found, or permanent repairs are made to damaged systems and
components. An approximate measure of this trend may be obtained by evaluating the
probability of structural and nonstructural damage states associated with LOF for the period of
time (number of days) following the earthquake. For example, consider LOF due to
nonstructural (NSA) damage. Referring to Table 6-7a, the LOF due to Slight NSA component
damage is 1 or 2 days for most occupancy types. So, at Day 1 after the earthquake, the
probability of temporary loss of function would be the probability of Slight, or greater, damage
to NSA components. After 3 days, however, the building is assumed to no longer be affected by
Slight damage (due to repairs or other solutions), but could still be affected by more serious
damage, since LOF due to Moderate NSA component damage would last at least 9 days, and the
probability of LOF at Day 3 would be the probability of Moderate, or greater, damage to NSA
components. The same logic can be used to find the probability of LOF for any given number of
days following the earthquake. As the number of days increases, the probability of contributing
damage states decreases. The same logic applies to LOF due to damage to the structural system.
For VA risk assessment, the probability of loss of function is calculated at nine periods of time
following the earthquake - Day 1, Day 3, Day 7 (1 week), Day 14 (2 weeks), Day 30 (1 month),
Day 60 (2 months) , Day 90 (3 months) , Day 180 (six months) and Day 360 (1 year). At each
period (i.e., Day x following the event), the probability of LOF, PLOFx, is the combination of the
probabilities of structural system (STR) damage states and nonstructural component (NSA)
damage states associated with LOF at Day x. These probabilities are assumed to be statistically
independent and combined using Equation (6-13).
PLOFx = PSTR Sds =i + PNSA Sds = j − PSTR Sds =i PNSA Sds = j
(6-13)
where:
5
PΣTR Σds =i = ∑ PΣTR ds
(6-14)
ds =i
5
PNΣA Σds = j = ∑ PNΣA ds
(6-15)
ds = j
PLOFx =
probability of loss of function x days after event (Day x).
PSTRSds=i = probability of state i, or greater, structural (STR) damage.
PNSASds=j = probability of state j, or greater, nonstructural (NSA) damage.
i =
lowest index of structural (STR) damage states for which the value of
LOFds,STR (ds = i) is greater than, or equal, to x (in days).
j =
lowest index of nonstructural (NSA) damage states for which the value
of LOFds,NSA (ds = j) is greater than, or equal, to x (in days).
LOFds,STR = see Equation (6-10).
LOFds,NSA = see Equation (6-12).
6-15
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
CHAPTER 7. RISK CALCULATION TOOL
7.1
Introduction
The Risk Calculation Tool (RCT) is a collection of Excel spreadsheets which implement the risk
assessment methods and data described in previous chapters. This chapter describes the RCT
and shows example seismic risk assessments for two buildings, Roseburg 1 and Prescott 107,
respectively. This chapter also describes a "risk point" ranking scheme for comparison of
building risk based on post-processing of damage and loss results, and shows example rankings
of the 52 VA buildings for "As-Is" and "Retrofit" building conditions, respectively.
The RCT is intended primarily for use by structural engineers who have expertise in building
seismic evaluation, earthquake ground motions and loss estimation methods. Specifically, users
should be familiar with the following:
(1)
Evaluation methods of ASCE 31, Seismic Evaluation of Existing Buildings, (ASCE,
2003), since results of ASCE 31 evaluations are the basis of key performance-related
properties of the RCT.
(2)
Earthquake ground motions developed by the USGS National Seismic Hazard Mapping
Program (NSHMP) for use in ASCE 7-10, Minimum Design Loads for Buildings and
Other Structures (ASCE, 2010), since these data are required by the RCT for each
medical center facility site of interest.
(3)
Earthquake loss estimation methods of the HAZUS technology, and specifically those of
the HAZUS Advance Engineering Building Module (AEBM, NIBS, 2002), since the
HAZUS AEBM technology is the basis for the methods of the RCT.
The spreadsheet approach of the RCT permits users to easily enter facility, building and ground
motion data, respectively, and to readily review and verify that these data are properly entered.
Further, spreadsheets provide transparency to calculations of building capacity, response,
damage and loss, allowing users to check values of interim parameters, as well as final values of
damage and loss. Users should be aware that while spreadsheets provide flexibility to the risk
calculation process, they are inherently susceptible to unintentional modification. Caution
should be exercised when saving copies of the program (e.g., after new input data are entered).
It is recommended that a "master copy" of the RCT be maintained as a back-up to working
copies of the program.
The version of the RCT (i.e., "100330 - RCT.xls") provided to the VA with this report is
configured for a 53-building portfolio 3 and includes all requisite facility, building ground motion
data for the 52 buildings of the 28 medical center facilities summarized in Table 1-1. As such,
the current version of the RCT can be run for any one, or all of the 52 buildings in the scope of
the current project without additional data entry. In future applications, the RCT will require reconfiguration and re-population of facility, building and ground motion databases for each
respective set of buildings of interest.
3
RCT portfolio includes the Memphis facility (614), although data for the Memphis 5 building are incomplete.
7-1
Seismic Risk Assessment of VA Hospital Buildings
7.2
RCT - Overview of Key Features and Use
7.2.1
Getting Started
Phase I Report- Approach and Methods
April 13, 2010
The Risk Calculation Tool (RCT) requires Excel software (i.e., software common to most
computers used by engineers). The Excel software should be set-up to automatically calculate
formulas and system security software (anti-virus software) should permit running of Excel
macros (Visual Basic routines).
If the user elects to save results data (which is recommended), the RCT will store output data in
separate Excel files using a pre-defined format of one of two "template" files. Unless the user
defines otherwise, the RCT assumes that these template files are located in the same folder as the
RCT, and saves files of output data in this folder.
7.2.2
User Operation
The RCT includes a very large number of spreadsheets (sheets), a limited number of which are
of general interest to users (although the complete set of sheets is available so the user can verify
data, calculations, etc.). Sheets of general interest include those with user-supplied (input) data
and risk assessment results. These sheets may be accessed directly, or by special Excel menu
commands (Add Ins) that allow users to control RCT operation, as described below:
RUN - User loads menu Add-Ins (with Program Menu button). Run Sheet also provides
technical notes and guidance to users. A screen shot of the Run Sheet is shown below.
7-2
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
RCT menu Add-Ins include the following:
VIEW - View menu includes the following options:
View Deficiencies ("Deficiencies DB" Sheet) - Allows users to view current list of
significant structural deficiencies (referred to therein as "deadly sins"). Note. The
RCT is configured to include the 22 significant structural deficiencies of Tables 2-11a
- 2-11c.
View Deficiencies for Buildings ("Performance DB" Sheet) - Allows users to view
(enter/edit) the significant structural deficiencies for each building in the current
portfolio. The Performance DB Sheet lists significant structural deficiencies for both
"As-Is" building conditions (based on ASCE 31 evaluations) and "Retrofit" building
conditions (based on the user modification of As-Is properties).
View Facilities ("Facilities DB" Sheet) - Allows users to view (enter/edit) list of medical
center facilities and related facility data corresponding to buildings in the current
portfolio.
View Ground Motions ("Ground Motions" Sheet) - Allows users to view (enter/edit) ground
motion data for each medical center facility corresponding to buildings in the current
portfolio.
View Buildings ("Building DB" Sheet) - Allows user to view (enter/edit) data for each
building in the "As-Is" building condition (based on ASCE 31 evaluations).
Note. The "Building DB 2" Sheet is identical in format to the Building DB Sheet and
contains data for each building in the "Retrofit" building conditions (based on the
users modification of As-Is properties).
View Results ("Results" Sheet) - Allows users to view results of the most current RCT risk
assessment. The Results Sheet contains all pertinent data, including input data (e.g.,
key building properties and ground motions), results of interim calculations (e.g.,
performance point calculation), and damage and loss results (e.g., expected values of
loss for Code ground motions and values of AAL for Probabilistic ground motions).
RUN - Run menu includes the following two options:
Run Single Building - Run Single Building dialog box requests users to:
(1) Select Facility - User selects facility from current list of medical centers.
(2) Select Building - User selects building of interest at the selected facility (from
buildings in the current portfolio).
(3) Select Ground Motion Type - User selects either Design (Code) or Probabilistic
ground motion (i.e., currently available ground motion types).
(4) Save Data? - User can elect to save results (recommended).
(5) Run Both Code and Probabilistic Ground Motions? User can elect to
simultaneously run both Design/Code and Probabilistic ground motions
(recommended).
7-3
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
The dialogue box shows the path and name of the output template file (e.g., "RCT
Output"), and the path and name of the file that will be used to save results (if the
user elects to save results). The user can modify these paths and file names, as
desired. A screen shot with the Run Single Building dialogue box is shown
below.
Run Multiple Buildings - Run Multiple Buildings dialog box requests users to:
(1) Select Facility, Building - User selects buildings of interest (using mouse) from
list of all buildings in current portfolio. Note. Memphis 614, Building 5 should
not be selected (since data are not complete for this building).
(2) Select Ground Motion Type - User selects either Design (Code) or Probabilistic
ground motion (currently available ground motion types).
(3) Save Data? - User can elect to save results (recommended).
The dialogue box shows the path and name of the output template file (e.g., "RCT
Output Multiple"), and the path and name of the file that will be used to save
results (if the user elects to save results). The user can modify these paths and file
names, as desired. A screen shot with the Run Multiple Building dialogue box is
shown below.
7-4
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
PLOT - Plot menu links to Plot Capacity Spectrum Method dialog box that requests users to:
(1)
Select Facility - User selects facility from current list of medical centers.
(2)
Select Building - User selects the building of interest at the selected facility (from
buildings in the current portfolio).
(3)
Select Ground Motion - User selects either Design (Code) or Probabilistic
ground motion (currently available ground motion types)
(4)
Select Intensity Level - User selects specific ground motion intensity (Design or
MCE intensity of Code ground motions, or one of the ten return-period intensities
of Probabilistic ground motions)
(5)
Plot Retrofit? User can elect to view the capacity-spectrum plot using building
properties corresponding to Retrofit building conditions.
The "Plot" Sheet illustrates the intersection of demand and capacity curves. Interested
users can visually verify the reasonableness of the capacity curve (considering selected
building properties), the reasonableness of the demand curve (considering selected
ground motion intensity), and the validity of the calculation of the performance point
(i.e., the intersection of capacity and demand curves).
A screen shot of an example capacity spectrum plot is shown below for the Roseburg 1
building, As-Is building conditions. In this case, the performance point occurs at Sd =
7.53 inches, for MCE ground motions (SA03 = 0.60g and SA10 = 0.90g) and building
capacity (Te = 0.99 seconds, and strength corresponding to Au = 0.199g).
7-5
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
For comparison, the screen shot below for same Roseburg 1 building, but with Retrofit
building conditions, shows the performance point occurs at Sd = 3.93 inches, for same
MCE ground motions (SA03 = 0.60g and SA10 = 0.90g), and but greatly improved
building capacity (Te = 0.81 seconds, and strength corresponding to Au = 0..623g).
7-6
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
QUIT - Quit menu ends the RCT without saving changes. Alternatively, the Excel program can
simply be exited without saving changes to the RCT. However, if user wishes to save
new or revised facility, building or ground motion data, then RCT should be saved before
exiting Excel.
7.2.3
Input Data
RCT requires users to input various facility, building and ground motion data in the following
database (DB) sheets of the RCT:
Deficiencies DB - User checks cells (add x's) of the "Deficiencies DB" Sheet indicating which
significant structural deficiencies apply to each building for "As-Is" and "Retrofit"
building conditions, respectively.
Facility DB - User inputs data into the Facility DB Sheet, including VISN no, facility no.,
medical center name, seismicity index (DVA H-18-08), and site class.
Ground Motion DB - User inputs data into the "Ground Motion DB" Sheet for each medical
center facility and ground motion intensity, including the site factor, peak ground
acceleration (PGA), 0.3-second response spectral acceleration (SA03) and 1.0 second
response spectral acceleration (SA10), and the duration index factor.
Building DB - User inputs data into the "Building DB" Sheet for each building in the As-Is
condition, including facility no., building no., building name, building use, area (sq, ft.),
number of beds (if known), occupancy data (if known), replacement cost data (if known),
model building type (MBT), height (no. of stories above and below grade), design
vintage (year), seismic coefficient (Cs), seismic design level (SDL), elastic period of the
building (if known), and seismic performance ratings, and data quality ratings, for the
structure (STR), nonstructural drift-sensitive (NSD) components, nonstructural
acceleration-sensitive (NSA) components, and contents (CON), respectively.
Building DB 2 Sheet - User inputs data into the Building DB 2" Sheet for each building in the
Retrofit condition (same data as Building DB sheet).
Note: RCT uses validation formatting of certain input cells of the "Building DB" and
"Building DB 2" to only except terms (i.e., spelling) appropriate for use in the RCT.
7.2.4
Output Data
The RCT copies results to "output" template files (if the user elects to save results) which are
saved using file names based on the date and time of the RCT run (e.g., 2010 - 3-30-20-20-5).
Template file structure (and hence output file structure) is described below:
RCT Output - The "RCT Output" template file is used for single-building analysis results. This
file includes raw results for Code ground motions ("RCT Results Code" Sheet), raw
results for Probabilistic ground motions ("RCT Results Probabilistic" Sheet), and four
7-7
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
sheets of post-processed data that summarize facility, building and ground motion data
("Building Data" Sheet), results of fragility calculations ("Engineering Results" Sheet),
and building damage and loss results ("VA Risk Results (1)" Sheet), and risk points ("VA
Results (2)" Sheet), respectively. Examples of the four sheets of post-processed data are
shown in Section 7.3.
RCT Output Multiple - "RCT Output Multiple" template file is used for multiple-building
analysis results. This file includes raw results for Code ground motions ("RCT Results
Code" Sheet), if Code ground motions are selected for multiple-building risk assessment,
and raw results for Probabilistic ground motions ("RCT Results Probabilistic" Sheet), if
Probabilistic ground motions are selected for risk assessment.
Raw data output sheets ("RCT Results Code" and "RCT Results Probabilistic") contain
all pertinent input data, interim calculation results and output data, and are similar in
format. The "RCT Results Code" Sheet requires fours rows of data for each building
corresponding to the building in As-Is and Retrofit conditions, and Design and MCE
ground motion intensity, respectively. The "RCT Results Probabilistic" Sheet requires
twenty (20) rows of data for each building corresponding to the building in As-Is and
Retrofit conditions, and ten Probabilistic ground motion intensities, respectively.
7.3
Example Evaluations of VA Buildings
Results of example seismic risk assessments are shown in Tables 7-1a - 7-1d for the Roseburg 1
building and in Tables 7-2a - 7-2d for the Prescott 107 building. Both buildings are relatively
large hospitals, built in the 1930's. However, the Roseburg 1 building is located in a region of
very high (VH) seismicity, while the Prescott 107 building is located in a region of moderate low
(ML) seismicity. Further, the Roseburg 1 building has a significant structural deficiency
(deflection compatibility) and is significantly weaker than the Prescott 107 building (which does
not have a significant structural deficiency).
Not surprisingly, the results of seismic assessments are very different for these two buildings in
their As-Is conditions. In the As-Is condition, the Roseburg 1 building poses a significant threat
to life safety (approximately 14 expected deaths or serious injuries for MCE ground motions and
ECO of the building), and has a 56% probability of at least Extensive structural for Design
ground motions, which indicates a significant threat to building function. In contrast, the
Prescott 107 building does not pose a significant threat to life safety (no expected deaths or
serious injuries for MCE ground motions and ECO of the building), and less than a 4%
probability of at least Extensive structure damage for Design ground motions, which indicates
little risk of loss function (other than that due to possible nonstructural and contents damage).
The results change dramatically for the Roseburg 1 building in the Retrofit condition, where
retrofit properties are based on seismic rehabilitation essentially complying with new building
seismic design requirements. In this case, expected casualties and the probability of at least
Extensive structural damage would be essentially nil. In contrast, only performance of
nonstructural systems and contents of Prescott 107 would be appreciably improved by seismic
rehabilitation (since performance of the As-Is structure is quite good).
7-8
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 7-1a. Example RCT table summarizing building data - Roseburg, Building 1
Facility and Site Data
Medical Center Name
20
Site Location (Lat/Long)
653
Site Condition
VH
General Building Data
Building Name
1
Occupancy (VA Sub-Name)
1933
Occupancy (HAZUS)
0
Model Building Type (HAZUS)
5
Building Area (sq. ft.)
1
Building Height, H (ft.)
493
Replacement Cost (dollars)
308
Contents Cost (dollars)
123
Code Ground Motion Data (ASCE 7-10)
Vision No.
Medical Center No.
VA Seismicity Rating (H-18-08)
Building No.
Year of Construction
Year of Remodel
No. of Stories (above grade)
No. of Stories (below grade)
No. of Occupants - Peak
No. of Occupants - ECO
No. of Beds
Roseburg, OR
43.2233
C
-123.365
Roseburg 1
Hospital
COM6
C3
123,320
81
$
80,158,000
$
80,158,000
Source-Type
MCE (w/Site Class)
DE (w/Site Class)
PGA
SA03
SA10
PGA
SA03
SA10
0.36
0.90
0.60
0.36
0.90
0.60
0.24
0.60
0.40
0.24
0.60
0.40
Key General Performance Properties
Building Condition
Building Name
As-Is (w/deficiencies)
Rehabilitated
Roseburg 1
0.046
0.133
Design Coefficient, Cs
Pre-Code
C3
Spec High
C2
Seismic Design Level/MBT
Poor
Baseline
Seismic Performance - STR
Poor
Very Poor
Baseline
Baseline
Seismic Performance - NSD/NSA
Very Poor
Baseline
Seismic Performance - CON
Good
Very Good
Data Quality - STR
Good
Good
Good
Good
Data Quality - NSD and NSA
Good
Good
Data Quality - CON
Summary of Structure Performance Ratings and Major Structural Deficiencies
Deficiency Check
Deficiency Check
Rating
Rating
None
None
Capacity - Overstrength
Baseline
Baseline
Gamma and Lambda Factors
Response - Duration
Degradation (Kappa) Factor
Damage State Median
Story Drift Ratio (Di)
None
Baseline
None
Baseline
Deflection Compat.
SubB
None
Baseline
None
Damage State Median
Mode Shape (a3) Factor
Baseline
Damage State Variability
Beta (b i) Factor
SubB
Casulaty Losses
Collapse Factor, P[COL|STR5]
SubB
None
Baseline
Deflection Compat.
None
Baseline
Deflection Compat.
None
Baseline
7-9
Seismic Risk Assessment of VA Hospital Buildings
Table 7-1b.
Phase I Report- Approach and Methods
April 13, 2010
Example RCT table summarizing engineering data - Roseburg, Building 1
Building Condition
As-Is (w/deficiencies)
Rehabilitated (new)
Key Performance Parameters
0.046
0.133
Design Coefficient, Cs
Pre-Code
C3
Spec High
C2
Seismic Design Level/MBT
Poor
Baseline
Seismic Performance - STR
Poor
Very Poor
Baseline
Baseline
Seismic Performance - NSD/NSA
Very Poor
Baseline
Seismic Performance - CON
Good
Very Good
Data Quality - STR
Good
Good
Good
Good
Data Quality - NSD and NSA
Good
Good
Data Quality - CON
Capacity Curve Properties
Elastic Period, Te (sec.)
0.99
0.81
Yield Displacement, Dy (in.)
1.04
2.02
Yield Acceleration, Ay (in.)
0.109
0.312
Ultimate Displacement, Du (in.)
7.75
16.42
Ultimate Acceleration, Au (in.)
0.199
0.623
Ground
Motions
Ground Motions
Response and Damage
Calculation
DE
MCE
DE
MCE
Building Name/No.
Roseburg 1
Response Properties
1.52
1.96
0.86
17.4%
20.6%
10.7%
0.183
0.199
0.381
Spectral Acceleration - SA (g)
Spectral Acceleration - SANSA (g)
0.197
0.239
0.345
Spectral Acceleration - SACON (g)
0.202
0.253
0.334
4.13
7.53
2.74
Spectral Displacement - SD (in.)
Story Drift - D/(H·a2/a3)
0.0087
0.0159
0.0058
Probability of Structural Damage State
21.8%
10.9%
45.6%
Slight Damage
14.7%
10.2%
12.6%
Moderate Damage
30.9%
30.4%
0.3%
Extensive Damage
25.0%
46.3%
0.0%
Complete Damage
Probability of Nonstructural (NSD) Damage State
26.2%
16.1%
32.4%
Slight Damage
25.7%
24.5%
30.9%
Moderate Damage
15.1%
21.2%
3.4%
Extensive Damage
12.9%
31.3%
0.5%
Complete Damage
Probability of Nonstructural (NSA) Damage State
40.4%
40.0%
27.1%
Slight Damage
21.6%
28.6%
2.7%
Moderate Damage
3.4%
5.8%
0.0%
Extensive Damage
1.0%
2.1%
0.0%
Complete Damage
Probability of Contents Damage State
40.5%
39.3%
25.1%
Slight Damage
22.4%
30.4%
2.3%
Moderate Damage
3.6%
6.6%
0.0%
Extensive Damage
1.1%
2.5%
0.0%
Complete Damage
Effective Period, Teff (sec.)
Effective Damping, b eff
7-10
0.95
16.8%
0.444
0.423
0.416
3.93
0.0083
49.8%
26.0%
1.3%
0.0%
29.3%
42.6%
7.7%
1.5%
38.5%
6.3%
0.2%
0.0%
37.6%
5.9%
0.1%
0.0%
Seismic Risk Assessment of VA Hospital Buildings
Table 7-1c.
Phase I Report- Approach and Methods
April 13, 2010
Example RCT table summarizing VA risk results (1) - Roseburg, Building 1
Building Condition
As-Is (w/deficiencies)
Rehabilitated (New)
Key Performance Parameters
0.133
0.046
Design Coefficient, Cs
Pre-Code
C3
Spec High
C2
Seismic Design Level/MBT
Poor
Baseline
Seismic Performance - STR
Poor
Very Poor
Baseline
Baseline
Seismic Performance - NSD/NSA
Very Poor
Baseline
Seismic Performance - CON
Good
Very Good
Data Quality - STR
Good
Good
Good
Good
Data Quality - NSD and NSA
Good
Good
Data Quality - CON
Ground Motions
Ground Motions
Risk Parameters
AAL
AAL
(x100)
Primary VA Objectives
(x100)
DE
MCE
DE
MCE
Building Name/No.
Roseburg 1
Probability of Structural (STR) Damage and Collapse
55.9%
76.7%
19.5%
0.3%
1.3%
0.4%
At Least Extensive - STR
6.2%
11.6%
2.0%
0.0%
0.0%
0.0%
Probability of Collapse
Probability of Damage to Nonstructural (NSD and NSA) Components and Contents (CON)
28.0%
52.5%
8.6%
3.9%
9.2%
1.6%
At Least Extensive - NSD
4.3%
7.9%
1.4%
0.0%
0.2%
0.0%
At Least Extensive - NSA
4.7%
9.2%
1.6%
0.0%
0.2%
0.1%
At Least Extensive - CON
Ground Motions
Ground Motions
Risk Parameters
AAL
AAL
Secondary VA Objectives
(x100)
(x100)
DE
MCE
DE
MCE
Expected Number of Casualties
7.5
13.6
2.4
0.02
4.7
8.5
1.5
0.01
1.6
2.9
0.5
0.00
1.0
1.8
0.3
0.00
3.1
5.7
1.0
0.00
1.9
3.6
0.6
0.00
Expected Economic Losses
22.4%
35.5%
9.0%
2.8%
Loss Ratio w/o Contents
$ 5,723 $ 7,964 $ 2,272 $
260 $
STR ($ in thousands)
$ 8,033 $ 14,287 $ 2,896 $ 1,646 $
NSD ($ in thousands)
$ 4,228 $ 6,244 $ 2,073 $
346 $
NSA ($ in thousands)
$ 4,329 $ 6,746 $ 2,870 $
303 $
Contents ($ in thousands)
Functional Losses
101
146
36
2
Expected LOF (days)
Probability of LOF due to Structural and Nonstructural Damage
90%
97%
15%
Day 1
90%
97%
15%
Day 3
78%
92%
15%
Day 7 (1 week)
78%
92%
0%
Day 14 (2 weeks)
58%
79%
0%
Day 30 (1 month)
56%
77%
0%
Day 60 (2 months)
56%
77%
0%
Day 90 (3 months)
25%
46%
0%
Day 180 (6 months)
0%
0%
0%
Day 360 (1 year)
Serious Injuries - Peak
Serious Injuries - ECO
Life-Threatening Injuries - Peak
Life-Threatening Injuries - ECO
Immediate Deaths - Peak
Immediate Deaths - ECO
7-11
0.05
0.03
0.00
0.00
0.00
0.00
4.9%
479
2,840
621
578
5
32%
32%
32%
2%
2%
1%
1%
0%
0%
0.01
0.01
0.00
0.00
0.00
0.00
$
$
$
$
1.0%
92
587
103
98
1
Seismic Risk Assessment of VA Hospital Buildings
Table 7-1d.
Phase I Report- Approach and Methods
April 13, 2010
Example RCT table summarizing VA risk results (2) - Roseburg, Building 1
Building Condition
As-Is (w/deficiencies)
Rehabilitated (New)
Key Performance Parameters
0.046
0.133
Design Coefficient, Cs
Pre-Code
C3
Spec High
C2
Seismic Design Level/MBT
Poor
Baseline
Seismic Performance - STR
Poor
Very Poor
Baseline
Baseline
Seismic Performance - NSD/NSA
Very Poor
Baseline
Seismic Performance - CON
Good
Very Good
Data Quality - STR
Good
Good
Good
Good
Data Quality - NSD and NSA
Good
Good
Data Quality - CON
Values of Risk Parameters
Risk Points
Total Risk Points - As-Is (w/Def.)
37.9
Risk Parameter
Value($M)
RCT
Threshold
Net
Rate
Points
Deaths and Injuries due to MCE Ground Motions - Effective Continuous Occupancy
Serious Injuries
8.5
8.5
0.5
4.2
Life-Threatening Inuries
1.8
1.8
1.0
1.8
Immediate Deaths
3.6
3.6
2.0
7.2
Risk Points - Casualties
13.2
Dollar Losses - Repair/Replacement Costs based on Average Annualized Loss (AAL x 100)
Structure (STR)
$11.2
20.3%
20.3%
5.0
1.0
Nonstructural (NSD)
$27.8
10.4%
10.4%
6.2
0.6
Nonstructural (NSA)
$41.1
5.0%
5.0%
9.2
0.5
Contents
$80.2
3.6%
3.6%
17.9
0.6
Risk Points - Dollar Losses
2.8
Downtime - Probability of at Least Extensive Damage due to DE Ground Motions
Structure (STR)
55.9%
55.9%
30
16.8
Nonstructural (NSD)
28.0%
28.0%
15
4.2
Nonstructural (NSA)
4.3%
4.3%
15
0.7
Contents (CON)
4.7%
4.7%
7.5
0.4
Risk Points - Downtime
22.0
Values of Risk Parameters
Risk Points
Total Risk Points - Rehab (new)
0.9
Risk Parameter
Value($M)
RCT
Threshold
Net
Rate
Points
Deaths and Injuries due to MCE Ground Motions - Effective Continuous Occupancy
Serious Injuries
0.0
0.0
0.5
0.0
Life-Threatening Inuries
0.0
0.0
1.0
0.0
Immediate Deaths
0.0
0.0
2.0
0.0
Risk Points - Casualties
0.0
Dollar Losses - Repair/Replacement Costs based on Average Annualized Loss (AAL x 100)
Structure (STR)
$11.2
0.8%
0.8%
5.0
0.0
Nonstructural (NSD)
$27.8
2.1%
2.1%
6.2
0.1
Nonstructural (NSA)
$41.1
0.3%
0.3%
9.2
0.0
Contents (CON)
$80.2
0.1%
0.1%
17.9
0.0
Risk Points - Dollar Losses
0.2
Downtime - Probability of at Least Extensive Damage due to DE Ground Motions
Structure (STR)
0.3%
0.3%
30
0.1
Nonstructural - Drift (NSD)
3.9%
3.9%
15
0.6
Nonstructural - Accel. (NSA)
0.0%
0.0%
15
0.0
Contents (CON)
0.0%
0.0%
7.5
0.0
Risk Points - Downtime
0.7
Building Name/No.
Roseburg 1
7-12
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 7-2a. Example RCT table summarizing building data - Prescott, Building 107
Facility and Site Data
Medical Center Name
18
Site Location (Lat/Long)
649
Site Condition
ML
General Building Data
Building Name
107
Occupancy (VA Sub-Name)
1937
Occupancy (HAZUS)
0
Model Building Type (HAZUS)
4
Building Area (sq. ft.)
1
Building Height, H (ft.)
396
Replacement Cost (dollars)
248
Contents Cost (dollars)
99
Code Ground Motion Data (ASCE 7-10)
Vision No.
Medical Center No.
VA Seismicity Rating (H-18-08)
Building No.
Year of Construction
Year of Remodel
No. of Stories (above grade)
No. of Stories (below grade)
No. of Occupants - Peak
No. of Occupants - ECO
No. of Beds
Prescott, AZ
34.7533
D
-112.0487
Prescott 107
Hospital
COM6
C2
99,027
47
$
64,367,550
$
64,367,550
Source-Type
MCE (w/Site Class)
DE (w/Site Class)
PGA
SA03
SA10
PGA
SA03
SA10
0.19
0.48
0.22
0.19
0.48
0.22
0.13
0.32
0.15
0.13
0.32
0.15
Key General Performance Properties
Building Condition
Building Name
As-Is (w/deficiencies)
Rehabilitated
Prescott 107
0.113
0.113
Design Coefficient, Cs
Pre-Code
C2
Low Code
C2
Seismic Design Level/MBT
Baseline
Baseline
Seismic Performance - STR
Poor
Very Poor
Baseline
Baseline
Seismic Performance - NSD/NSA
Very Poor
Baseline
Seismic Performance - CON
Good
Very Good
Data Quality - STR
Good
Good
Good
Good
Data Quality - NSD and NSA
Good
Good
Data Quality - CON
Summary of Structure Performance Ratings and Major Structural Deficiencies
Deficiency Check
Deficiency Check
Rating
Rating
None
None
Capacity - Overstrength
Baseline
Baseline
Gamma and Lambda Factors
None
Response - Duration
Degradation (Kappa) Factor
Baseline
Damage State Median
Story Drift Ratio (Di)
Baseline
Damage State Median
Mode Shape (a3) Factor
Baseline
Damage State Variability
Beta (b i) Factor
Baseline
Casulaty Losses
Collapse Factor, P[COL|STR5]
Baseline
None
Baseline
None
None
Baseline
None
None
Baseline
None
None
Baseline
None
None
Baseline
7-13
Seismic Risk Assessment of VA Hospital Buildings
Table 7-2b.
Phase I Report- Approach and Methods
April 13, 2010
Example RCT table summarizing engineering data - Prescott, Building 107
Building Condition
As-Is (w/deficiencies)
Rehaβilitated (new)
Key Performance Parameters
0.113
0.113
Design Coefficient, Cs
Pre-Code
C2
Low Code
C2
Seismic Design Level/MBT
Baseline
Baseline
Seismic Performance - STR
Poor
Very Poor
Baseline
Baseline
Seismic Performance - NSD/NSA
Very Poor
Baseline
Seismic Performance - CON
Good
Very Good
Data Quality - STR
Good
Good
Good
Good
Data Quality - NSD and NSA
Good
Good
Data Quality - CON
Capacity Curve Properties
Elastic Period, Te (sec.)
0.66
0.62
Yield Displacement, Dy (in.)
1.19
1.05
Yield Acceleration, Ay (in.)
0.282
0.282
Ultimate Displacement, Du (in.)
10.49
9.29
Ultimate Acceleration, Au (in.)
0.564
0.564
Ground Motions
Ground Motions
Response and Damage
Calculation
DE
MCE
DE
MCE
Building Name/No.
Prescott 107
Response Properties
0.66
0.66
0.62
7.0%
7.2%
7.0%
0.203
0.301
0.216
Spectral Acceleration - SA (g)
Spectral Acceleration - SANSA (g)
0.181
0.269
0.190
Spectral Acceleration - SACON (g)
0.174
0.258
0.181
0.86
1.29
0.81
Spectral Displacement - SD (in.)
Story Drift - D/(H·a2/a3)
0.0029
0.0044
0.0028
Proβaβility of Structural Damage State
26.7%
28.7%
23.5%
Slight Damage
18.8%
28.6%
6.0%
Moderate Damage
3.3%
7.6%
0.2%
Extensive Damage
0.3%
0.9%
0.0%
Complete Damage
Proβaβility of Nonstructural (NSD) Damage State
22.8%
27.8%
22.7%
Slight Damage
10.2%
16.7%
9.9%
Moderate Damage
3.0%
6.4%
0.4%
Extensive Damage
1.1%
3.2%
0.0%
Complete Damage
Proβaβility of Nonstructural (NSA) Damage State
39.5%
38.2%
39.0%
Slight Damage
18.6%
32.5%
6.6%
Moderate Damage
2.6%
7.7%
0.2%
Extensive Damage
0.7%
3.1%
0.0%
Complete Damage
Proβaβility of Contents Damage State
38.9%
39.0%
36.5%
Slight Damage
17.2%
31.1%
5.5%
Moderate Damage
2.2%
7.0%
0.1%
Extensive Damage
0.6%
2.7%
0.0%
Complete Damage
Effective Period, Teff (sec.)
Effective Damping, β eff
7-14
0.63
7.8%
0.310
0.275
0.263
1.19
0.0041
34.7%
15.4%
1.0%
0.0%
29.8%
19.6%
1.4%
0.1%
51.1%
21.0%
1.5%
0.2%
50.7%
18.8%
1.2%
0.1%
Seismic Risk Assessment of VA Hospital Buildings
Table 7-2c.
Phase I Report- Approach and Methods
April 13, 2010
Example RCT table summarizing VA risk results (1) - Prescott, Building 107
Building Condition
As-Is (w/deficiencies)
Rehabilitated (New)
Key Performance Parameters
0.113
0.113
Design Coefficient, Cs
Pre-Code
C2
Low Code
C2
Seismic Design Level/MBT
Baseline
Baseline
Seismic Performance - STR
Poor
Very Poor
Baseline
Baseline
Seismic Performance - NSD/NSA
Very Poor
Baseline
Seismic Performance - CON
Good
Very Good
Data Quality - STR
Good
Good
Good
Good
Data Quality - NSD and NSA
Good
Good
Data Quality - CON
Ground Motions
Ground Motions
Risk Parameters
AAL
AAL
(x100)
Primary VA Objectives
(x100)
DE
MCE
DE
MCE
Building Name/No.
Prescott 107
Probability of Structural (STR) Damage and Collapse
3.6%
8.5%
1.4%
0.2%
1.1%
0.2%
At Least Extensive - STR
0.0%
0.1%
0.0%
0.0%
0.0%
0.0%
Probability of Collapse
Probability of Damage to Nonstructural (NSD and NSA) Components and Contents (CON)
4.1%
9.6%
1.6%
0.4%
1.5%
0.2%
At Least Extensive - NSD
3.3%
10.8%
1.0%
0.2%
1.6%
0.1%
At Least Extensive - NSA
2.8%
9.7%
0.9%
0.1%
1.3%
0.1%
At Least Extensive - CON
Ground Motions
Ground Motions
Risk Parameters
AAL
AAL
Secondary VA Objectives
(x100)
(x100)
DE
MCE
DE
MCE
Expected Number of Casualties
0.1
0.2
0.0
0.01
0.0
0.1
0.0
0.01
0.0
0.0
0.0
0.00
0.0
0.0
0.0
0.00
0.0
0.0
0.0
0.00
0.0
0.0
0.0
0.00
Expected Economic Losses
6.9%
14.8%
2.3%
1.5%
Loss Ratio w/o Contents
$
391 $
737 $
169 $
106 $
STR ($ in thousands)
$ 1,252 $ 2,541 $
502 $
374 $
NSD ($ in thousands)
$ 2,825 $ 6,224 $
840 $
511 $
NSA ($ in thousands)
$ 2,512 $ 5,628 $
711 $
437 $
Contents ($ in thousands)
Functional Losses
9
17
3
1
Expected LOF (days)
Probability of LOF due to Structural and Nonstructural Damage
70%
88%
13%
Day 1
70%
88%
13%
Day 3
39%
64%
13%
Day 7 (1 week)
25%
48%
0%
Day 14 (2 weeks)
7%
18%
0%
Day 30 (1 month)
4%
11%
0%
Day 60 (2 months)
4%
9%
0%
Day 90 (3 months)
0%
1%
0%
Day 180 (6 months)
0%
0%
0%
Day 360 (1 year)
Serious Injuries - Peak
Serious Injuries - ECO
Life-Threatening Injuries - Peak
Life-Threatening Injuries - ECO
Immediate Deaths - Peak
Immediate Deaths - ECO
7-15
0.02
0.02
0.00
0.00
0.00
0.00
3.6%
249
759
1,329
1,164
3
35%
35%
35%
3%
3%
1%
1%
0%
0%
0.00
0.00
0.00
0.00
0.00
0.00
$
$
$
$
0.5%
39
141
143
116
0
Seismic Risk Assessment of VA Hospital Buildings
Table 7-2d.
Phase I Report- Approach and Methods
April 13, 2010
Example RCT table summarizing VA risk results (2) - Prescott, Building 107
Building Condition
As-Is (w/deficiencies)
Rehabilitated (New)
Key Performance Parameters
0.113
0.113
Design Coefficient, Cs
Pre-Code
C2
Low Code
C2
Seismic Design Level/MBT
Baseline
Baseline
Seismic Performance - STR
Poor
Very Poor
Baseline
Baseline
Seismic Performance - NSD/NSA
Very Poor
Baseline
Seismic Performance - CON
Good
Very Good
Data Quality - STR
Good
Good
Good
Good
Data Quality - NSD and NSA
Good
Good
Data Quality - CON
Values of Risk Parameters
Risk Points
Total Risk Points - As-Is (w/Def.)
3.1
Risk Parameter
Value($M)
RCT
Threshold
Net
Rate
Points
Deaths and Injuries due to MCE Ground Motions - Effective Continuous Occupancy
Serious Injuries
0.1
0.1
0.5
0.1
Life-Threatening Inuries
0.0
0.0
1.0
0.0
Immediate Deaths
0.0
0.0
2.0
0.1
Risk Points - Casualties
0.1
Dollar Losses - Repair/Replacement Costs based on Average Annualized Loss (AAL x 100)
Structure (STR)
$9.0
1.9%
1.9%
4.5
0.1
Nonstructural (NSD)
$22.3
2.2%
2.2%
5.6
0.1
Nonstructural (NSA)
$33.0
2.5%
2.5%
8.2
0.2
Contents
$64.4
1.1%
1.1%
16.0
0.2
Risk Points - Dollar Losses
0.6
Downtime - Probability of at Least Extensive Damage due to DE Ground Motions
Structure (STR)
3.6%
3.6%
30
1.1
Nonstructural (NSD)
4.1%
4.1%
15
0.6
Nonstructural (NSA)
3.3%
3.3%
15
0.5
Contents (CON)
2.8%
2.8%
7.5
0.2
Risk Points - Downtime
2.4
Values of Risk Parameters
Risk Points
Total Risk Points - Rehab (new)
0.3
Risk Parameter
Value($M)
RCT
Threshold
Net
Rate
Points
Deaths and Injuries due to MCE Ground Motions - Effective Continuous Occupancy
Serious Injuries
0.0
0.0
0.5
0.0
Life-Threatening Inuries
0.0
0.0
1.0
0.0
Immediate Deaths
0.0
0.0
2.0
0.0
Risk Points - Casualties
0.0
Dollar Losses - Repair/Replacement Costs based on Average Annualized Loss (AAL x 100)
Structure (STR)
$9.0
0.4%
0.4%
4.5
0.0
Nonstructural (NSD)
$22.3
0.6%
0.6%
5.6
0.0
Nonstructural (NSA)
$33.0
0.4%
0.4%
8.2
0.0
Contents (CON)
$64.4
0.2%
0.2%
16.0
0.0
Risk Points - Dollar Losses
0.1
Downtime - Probability of at Least Extensive Damage due to DE Ground Motions
Structure (STR)
0.2%
0.2%
30
0.1
Nonstructural - Drift (NSD)
0.4%
0.4%
15
0.1
Nonstructural - Accel. (NSA)
0.2%
0.2%
15
0.0
Contents (CON)
0.1%
0.1%
7.5
0.0
Risk Points - Downtime
0.2
Building Name/No.
Prescott 107
7-16
Seismic Risk Assessment of VA Hospital Buildings
7.4
Phase I Report- Approach and Methods
April 13, 2010
Risk Point Ranking Scheme
At the request of the VA, a "risk point" ranking scheme was developed for comparing the
relative seismic risk of different buildings using a single risk parameter. This is an inherently
difficult task, which must necessarily consider different sources of risk in an equitable manner
and incorporate VA perspective on each of these sources of risk.
In general, buildings have a different mixture of the relative amount of seismic risk due to
casualties, economic loss and loss of function, respectively. Some buildings are more risky in
terms of casualties, or economic losses than others, but less risky in terms of loss of function, etc.
Ranking based on a single parameter will necessarily be different depending on the scheme used
to combine individual sources of risk.
While each source of risk is important, the VA has indicated that loss of function should be
considered the most important risk parameter. Further, the VA has indicated that certain
occupancies (e.g., boiler plants and hospitals) should be considered more important than others
in terms of the need to avoid loss of function.
The scheme developed for the VA assigns "risk points" to key measure(s) of risk in each of the
three risk categories, casualty risk, economic risk and function risk. The greater the risk, the
larger the number of risk points. Key measures of casualty, economic and functional risk are
described below.
Casualty Risk - Casualty risk is measured by: (1) immediate deaths, (2) life-threatening injuries
and (3) serious injuries requiring hospitalization. Consistent with the life safety objectives of
ASCE 7-10, expected number of casualties are based on MCE ground motions. More risk points
are assigned to deaths than injuries, recognizing that avoiding deaths is of greater importance
than avoiding injuries.
Economic Risk - Economic risk is measured by dollar losses associated with repair/replacement
of damage to the structure, nonstructural (NSD) components, nonstructural (NSA) components
and contents, respectively. Economic losses are based on estimates of average annualized loss
(AAL) so that facilities in areas of high seismicity, more likely to experience damaging ground
motions, are assigned more risk points than comparable facilities in areas of low seismicity
where damaging ground motions are infrequent. All else equal, more risk points are assigned to
the AAL associated with the structure, recognizing the greater importance of structural costs to
the total cost of repair/replacement of building systems. The total value of the building is
discounted so that very large buildings do not overly dominate economic risk.
Functional Risk - Functional risk is measured by the probability of Extensive or greater damage
to the structure, nonstructural (NSD) components, nonstructural (NSA) components and
contents, respectively. Consistent with operational objectives of critical facilities, functional risk
is based on damage due to Design ground motions - that is, critical facilities should remain
functional for earthquake ground motions likely to occur at the facility site. Ideally, these
ground motions would be based on deterministic ground motions representing the event
(magnitude/distance) that controls hazard at the facility site, but such ground motions are not
7-17
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
available at this time, and Design ground motions are used as a surrogate for likely ground
motions. All else equal, more risk points are assigned to the probability of Extensive or greater
damage to the structure, recognizing the greater importance of structural damage to building
function.
Table 7-3 summarizes the specific risk parameters and associated risk point rates used to
calculate risk points for casualty risk, economic risk and functional risk, respectively. Values of
risk parameters are taken form the results of the RCT. As shown in the table, values of each risk
parameter (RCT) are factored by an associated risk point rate (PR) to obtain the number of risk
points associated with the parameter of interest.
Table 7-3 Summary of risk parameters and risk point rates used to calculate risk points
associated with casualty risk, economic risk and function risk, respectively.
Risk Subject
Risk Parameter
(RCT)
Risk Points Rate
(PR)
Risk Points
(RCT x PR)
Casualty Risk - Deaths and Injuries due to MCE Ground Motions - Effective Continuous Occupancy1
No. of Serious Injuries (S2)
NS2
0.5
0.5 x NS2
No. of Life-Threatening Injuries (S3)
NS3
1.0
1.0 x NS3
No. Immediate Deaths (S4)
NS4
2.0
2.0 x NS4
Σ(RCT x PR)S2-S4
Casualty Risk Points
Economic Risk - Repair/Replacement Costs based on Average Annualized Loss (AAL x 100)2
100*AALSTR
4*FVSTR*(RVB)1/2
400*AALSTR*FVSTR*(RVB)1/2
Dollar Loss - Nonstructural (NSD)
100*AALNSD
2*FVNSD*(RVB)
1/2
200*AALNSD*FVNSD*(RVB)1/2
Dollar Loss - Nonstructural (NSA)
100*AALNSA
2*FVNSA*(RVB)1/2
200*AALNSA*FVNSA*(RVB)1/2
Dollar Loss - Contents (CON)
100*AALCON
2*FVCON*(RVB)1/2
200*AALCON*FVCON*(RVB)1/2
Dollar Loss - Structure (STR)
Σ(RCT x PR)AAL
Economic Risk Points
Function Risk - Probability of Extensive (4) or Complete (5) Damage due to Design Ground Motions3,4
LOF - Structure (STR)
PSTR4 + PSTR5
4*LOFROT
4*LOFROT*(PSTR4 + PSTR5)
LOF - Nonstructural (NSD)
PNSD4 + PNSD6
2*LOFROT
2*LOFROT*(PNSD4 + PNSD5)
LOF - Nonstructural (NSA)
PNSA4 + PNSA7
2*LOFROT
2*LOFROT*(PNSA4 + PNSA5)
LOF - Contents (CON)
PCON4 + PCON8
1*LOFROT
1*LOFROT*(PCON4 + PCON5)
Σ(RCT x PR)LOF
Function Risk Points
1. No. of immediate deaths (NS2), life-threatening injuries (NS3) and serious injuries (NS4) , respectively, based on
effective continuous occupants (ECO) in building and results of RCT Sheet "VA Risk Results (1)"
2. Average Annualized Loss (AAL) ratio due to damage to the structure (AALSTR), nonstructural NSD components
(AALNSD), nonstructural NSA components (AALNSD) and contents (AALCON), respectively, based on Equation (6-2).
Replacement value of building (RVB) taken form RCT Sheet "Building Data" and fractions of total replacement value
of the structure (FVSTR), nonstructural NSD components (FVNSD), nonstructural NSA components (FVNSA) and
contents (FVCON), respectively, taken from RCT Sheet "RCT Output Probabilistic".
3. Probability of at least Extensive damage to the structure (PSTR4 + PSTR5), nonstructural NSD components
(PNSD4 + PNSD5), nonstructural NSA components (PNSA4 + PNSA5) and contents (PCON4 + PCON5), respectively,
taken from results of RCT Sheet "VA Risk Results (1)".
4. Values of the loss of function rate factor for each occupancy type (LOFROT) are as follows: 15.0 for Boiler Plants,
7.5 for Hospitals, 2.5 for Offices and 5.0 for all other occupancy types.
7-18
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Risk point rates reflect the relative importance of the risk parameter of interest. An iterative
process was used to establish balance between casualty risk points, economic risk points and
function risk points, respectively. The risk point rates shown in Table 7-3 achieve roughly equal
risk points for casualty and economic risk, and about twice as many risk points for function risk
when taken in total for the portfolio of 52 VA buildings (As-Is condition). That is, these rates
emphasize importance of loss of function to total risk. The rates are set such that the most risky
building in the portfolio of 52 VA buildings has about 100 total risk points (i.e., total of risk
points associated with casualty, economic and functional risk, respectively).
7.5
Example Risk Point Ranking of 52 VA Buildings
Example risk point ranking of the 52 VA buildings is shown in Tables 7.4a - 7.4b for the
buildings in the As-Is (actual) condition, and in Tables 7.5a - 7-5b for the buildings in the
Retrofit (hypothetical rehabilitation) condition. In these tables, buildings are ranked in terms of
total risk points, but also show individual risk points associated with casualty risk, economic risk
and functional risk. Risk point cells are shaded (colored) to emphasize transition from values of
larger to smaller risk points. A number of other data are provided in these tables to permit
comparison with of seismic risk with seismicity (VA index), ground motions (MCE), exposure
data including occupancy type, replacement value, and number of effective continuous occupants
(ECO), building properties including, age (year), height (No. of Flrs.), model building type
(MBT), elastic period (Te), seismic design coefficient (Cs), and seismic design level (SDL), and
seismic performance ratings of the structure (STR), nonstructural drift-sensitive components
(NSD) and nonstructural acceleration-sensitive components (NSA and contents (CON).
Tables 7-4a - 7-4b show a wide range of total risk points for As-Is buildings ranging from 97.3
risk points for the San Juan 1 building to 1.3 risk points for the seismically-rehabilitated
Martinez 5/R-1 building (blue shading in Table 7-3 indicates buildings that have been
seismically rehabilitated). The San Juan 1 building is a very large building, located in a high
seismic region with a relatively weak, steel-frame with masonry infill walls, rated Very Poor due
to multiple significant structural deficiencies. While this building is not the most risky in terms
of life safety (Boston 1), dollar loses (W. Los Angeles 500) or loss of function (White City 232),
it has significant risk in each category.
The Boston 1 building is most risky in terms of life safety, since it is very large (tall), very weak,
non-ductile concrete frame structure with multiple significant structural deficiencies. While
located in a region of low seismicity, should MCE ground motions occur (very unlikely); the
building will suffer severe structural damage and possibly collapse. The W. Los Angeles 500
building is most risky in terms of dollar losses since it is a very large building, with structural
issues, located in a region of very high seismicity, for which damaging ground motions are likely
to occur. The White City 232 building is most risky in terms of loss of function, since it used as
a Boiler Plant (special risk points), has structural issues and is located in a high seismic region.
Except in regions of high or very high seismicity, Tables 7-5a - 7-5b show relatively small
values of total risk points for Retrofit (like new) buildings. While casualty risk is low, in all
cases, economic and functional risk can be significant due to damage to nonstructural
components and contents (which are difficult to fully protect in regions of high seismicity).
7-19
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 7.4a. Example ranking of 52 VA buildings using total Risk Points - building properties
based on As-Is conditions
Risk Points
Building Name
Deaths
Injuries
Dollar
Loss
Facility
Function
Total
VA
Seis.
San Juan 1
W. Los Angeles 500
Reno 1
Boston 1
W. Los Angeles 114
Seattle 100NT
Portland 100
San Francisco 6
W. Los Angeles 205
Albuquerque 1
New York 1
San Francisco 1
American Lake 81
Ft. Harrison 154
San Francisco 9
Roseburg 1
Marion 14
Reno 1A
Roseburg 2
Palo Alto 6
Marion 8
White City 204
Nashville 1
San Diego 2
N. Little Rock 69
Columbia 8
Columbia 1
Palo Alto 54
East Orange 8
Sepulveda 103
Albuquerque 10
Sepulveda 99
N. Little Rock 66
Anchorage 3001
Boston 5
San Diego 1
Seattle 13
Walla Walla 69
Long Beach 126A
Prescott 117
Montrose 20
American Lake 61
Walla Walla 76
White City 232
Prescott 107
East Orange 7
Portland 6
White River Jt. 2
Long Beach 138
Montrose 10
Ft. Harrison 154A
Martinez 5/R-1
36.3
11.6
20.3
66.8
10.8
12.1
23.8
9.8
4.3
33.7
41.6
6.5
4.5
10.8
1.3
13.2
0.0
10.1
12.0
4.0
2.6
3.7
17.0
0.0
0.1
0.0
3.2
0.2
0.1
0.0
2.1
3.5
1.5
0.1
0.1
0.3
0.1
0.8
0.1
0.3
0.0
0.0
0.0
0.0
0.1
0.3
0.0
0.0
0.0
0.4
0.0
0.0
33.4
51.3
26.6
3.4
31.0
21.7
15.1
21.7
15.2
4.7
2.4
18.0
12.0
4.2
5.5
2.8
0.6
10.2
2.2
15.5
1.2
0.9
0.8
2.8
0.2
0.3
1.1
5.3
0.2
2.0
0.7
1.2
0.5
3.0
0.1
3.9
0.9
0.7
1.6
0.2
0.1
1.1
0.1
0.1
0.6
0.2
0.5
0.1
0.9
0.2
0.3
0.6
27.6
29.3
39.5
9.9
25.9
33.6
22.9
28.6
38.8
19.0
11.5
27.3
28.5
26.9
32.4
22.0
32.6
12.7
16.1
8.2
23.6
19.3
3.4
18.3
20.5
19.1
8.0
6.4
10.8
8.2
6.9
3.1
5.1
3.8
6.6
2.4
4.2
3.7
2.8
3.4
3.6
2.3
3.3
3.1
2.4
2.3
2.0
2.3
1.3
1.6
1.5
0.7
97.3
92.2
86.4
80.1
67.7
67.4
61.8
60.1
58.3
57.4
55.5
51.8
45.0
41.9
39.2
38.0
33.2
33.0
30.3
27.7
27.4
23.9
21.2
21.1
20.8
19.4
12.3
11.9
11.1
10.2
9.7
7.8
7.1
6.8
6.8
6.6
5.2
5.2
4.5
3.9
3.7
3.4
3.4
3.2
3.1
2.8
2.5
2.4
2.2
2.2
1.8
1.3
H
VH
VH
ML
VH
VH
H
VH
VH
MH
MH
VH
H
MH
VH
VH
H
VH
VH
VH
H
MH
ML
VH
MH
MH
MH
VH
MH
VH
MH
VH
MH
VH
ML
VH
VH
MH
VH
ML
ML
H
MH
MH
ML
MH
H
ML
VH
ML
MH
VH
7-20
MCE Ground Motions
PGA
(g)
0.41
0.89
0.73
0.14
0.89
0.59
0.42
0.79
0.89
0.26
0.28
0.79
0.52
0.36
0.79
0.36
0.41
0.73
0.36
0.73
0.41
0.28
0.12
0.49
0.22
0.25
0.25
0.73
0.18
0.85
0.26
0.85
0.22
0.60
0.14
0.49
0.59
0.23
0.63
0.19
0.16
0.52
0.23
0.28
0.19
0.18
0.42
0.15
0.63
0.16
0.36
0.67
SA0.3s SA1.0s
(g)
(g)
1.02
2.23
1.83
0.35
2.23
1.47
1.05
1.97
2.23
0.65
0.69
1.97
1.29
0.91
1.97
0.90
1.01
1.83
0.90
1.82
1.01
0.71
0.30
1.23
0.54
0.63
0.63
1.82
0.44
2.13
0.65
2.13
0.54
1.50
0.35
1.23
1.47
0.57
1.57
0.48
0.41
1.29
0.57
0.71
0.48
0.44
1.05
0.38
1.57
0.41
0.91
1.66
0.57
1.24
0.93
0.17
1.24
0.85
0.62
1.39
1.24
0.32
0.25
1.39
0.77
0.52
1.39
0.60
0.70
0.93
0.60
1.16
0.70
0.48
0.15
0.72
0.31
0.33
0.33
1.16
0.17
1.43
0.32
1.43
0.31
1.02
0.17
0.72
0.85
0.31
0.88
0.22
0.17
0.77
0.31
0.48
0.22
0.17
0.62
0.20
0.88
0.17
0.52
0.92
Building Exposure Data
Occupancy
Value
($M)
ECO
Hospital
Hospital
Hospital
Hospital
Research
Hospital
Hospital
Research
Hospital
Long-Term
Hospital
Research
Hospital
Hospital
Long-Term
Hospital
Boiler Plant
Offices
Long-Term
Offices
Long-Term
Domiciliary
Hospital
Boiler Plant
Boiler Plant
Boiler Plant
Educational
Research
Boiler Plant
Research
Research
Domiciliary
Outpatient
Domiciliary
Boiler Plant
Hospital
Research
Long-Term
Research
Outpatient
Boiler Plant
Long-Term
Boiler Plant
Boiler Plant
Hospital
Research
Research
Boiler Plant
Research
Domiciliary
Outpatient
Research
$769
$1,218
$179
$904
$105
$202
$890
$78
$69
$78
$903
$57
$91
$172
$8
$160
$6
$18
$74
$46
$10
$12
$810
$23
$6
$10
$67
$45
$12
$4
$35
$41
$50
$23
$8
$1,111
$29
$53
$122
$13
$9
$36
$5
$16
$129
$38
$33
$11
$92
$37
$27
$20
1,478
2,343
345
1,739
350
388
1,712
261
133
285
1,737
189
175
331
29
308
5
118
270
310
36
91
1,557
19
5
8
192
150
10
12
115
305
226
171
7
2,137
97
193
405
61
8
132
4
13
248
126
110
9
308
274
123
66
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 7.4b. Example ranking of 52 VA buildings using total Risk Points - building properties
based on As-Is conditions
Risk Points
Performance Data
Building Properties
Building Name
Deaths
Injuries
Dollar
Loss
Facility
Function
Total
Year
Flrs.
San Juan 1
W. Los Angeles 500
Reno 1
Boston 1
W. Los Angeles 114
Seattle 100NT
Portland 100
San Francisco 6
W. Los Angeles 205
Albuquerque 1
New York 1
San Francisco 1
American Lake 81
Ft. Harrison 154
San Francisco 9
Roseburg 1
Marion 14
Reno 1A
Roseburg 2
Palo Alto 6
Marion 8
White City 204
Nashville 1
San Diego 2
N. Little Rock 69
Columbia 8
Columbia 1
Palo Alto 54
East Orange 8
Sepulveda 103
Albuquerque 10
Sepulveda 99
N. Little Rock 66
Anchorage 3001
Boston 5
San Diego 1
Seattle 13
Walla Walla 69
Long Beach 126A
American Lake 61
Prescott 117
Montrose 20
Walla Walla 76
White City 232
Prescott 107
East Orange 7
Portland 6
White River Jt. 2
Long Beach 138
Montrose 10
Ft. Harrison 154A
Martinez 5/R-1
36.3
11.6
20.3
66.8
10.8
12.1
23.8
9.8
4.3
33.7
41.6
6.5
4.5
10.8
1.3
13.2
0.0
10.1
12.0
4.0
2.6
3.7
17.0
0.0
0.1
0.0
3.2
0.2
0.1
0.0
2.1
3.5
1.5
0.1
0.1
0.3
0.1
0.8
0.1
0.0
0.3
0.0
0.0
0.0
0.1
0.3
0.0
0.0
0.0
0.4
0.0
0.0
33.4
51.3
26.6
3.4
31.0
21.7
15.1
21.7
15.2
4.7
2.4
18.0
12.0
4.2
5.5
2.8
0.6
10.2
2.2
15.5
1.2
0.9
0.8
2.8
0.2
0.3
1.1
5.3
0.2
2.0
0.7
1.2
0.5
3.0
0.1
3.9
0.9
0.7
1.6
1.1
0.2
0.1
0.1
0.1
0.6
0.2
0.5
0.1
0.9
0.2
0.3
0.6
27.6
29.3
39.5
9.9
25.9
33.6
22.9
28.6
38.8
19.0
11.5
27.3
28.5
26.9
32.4
22.0
32.6
12.7
16.1
8.2
23.6
19.3
3.4
18.3
20.5
19.1
8.0
6.4
10.8
8.2
6.9
3.1
5.1
3.8
6.6
2.4
4.2
3.7
2.8
2.3
3.4
3.6
3.3
3.1
2.4
2.3
2.0
2.3
1.3
1.6
1.5
0.7
97.3
92.2
86.4
80.1
67.7
67.4
61.8
60.1
58.3
57.4
55.5
51.8
45.0
41.9
39.2
38.0
33.2
33.0
30.3
27.7
27.4
23.9
21.2
21.1
20.8
19.4
12.3
11.9
11.1
10.2
9.7
7.8
7.1
6.8
6.8
6.6
5.2
5.2
4.5
4.4
3.9
3.7
3.4
3.2
3.1
2.8
2.5
2.4
2.2
2.2
1.8
1.3
1968
1976
1945
1952
1930
1981
1988
1933
1937
1932
1954
1933
1947
1963
1932
1933
1941
1937
1933
1960
1941
1942
1960
1972
1936
1932
1932
1981
1950
1986
1932
1974
1944
2006
1952
2006
2006
1906
2006
2006
1975
1950
2006
2006
1937
1950
2006
1938
2006
1950
2006
2006
11
7
7
14
3
8
9
4
3
5
19
4
4
4
2
5
1
3
3
3
2
2
4
1
1
1
3
2
1
1
2
1
3
1
1
6
2
2
3
2
1
1
1
2
4
2
3
1
2
3
1
1
7-21
MBT
Te
(sec.)
Cs
SDL
STR
NSD
NSA
(CON)
S4
S2
C2
C1
C3
S2
S2
C2
C2
C3
S5
C2
C3
C3
C2
C3
C2
C2
C3
C2
C3
URM
C3
C2
URM
S5
C3
S4
S5
RM1
C3
RM1
C3
W1
S5
S2
RM2
URM
C2
C2
S1
S5
RM1
RM1
C2
S5
C2
C2
C2
C3
C2
S3
2.00
1.72
1.04
3.35
0.61
2.01
2.19
0.69
0.66
0.88
2.37
0.79
0.73
0.66
0.38
0.99
0.49
0.60
0.64
0.69
0.40
0.41
0.85
0.41
0.48
0.41
0.62
0.39
0.46
0.25
0.38
0.26
0.66
0.34
0.70
1.49
0.46
0.68
0.57
0.43
0.39
0.58
0.31
0.41
0.66
0.50
0.44
0.27
0.34
0.58
0.35
0.27
0.03
0.26
0.10
0.01
0.10
0.04
0.04
0.09
0.06
0.03
0.01
0.10
0.09
0.03
0.08
0.05
0.07
0.17
0.06
0.08
0.04
0.03
0.01
0.15
0.03
0.05
0.09
0.15
0.02
0.14
0.11
0.14
0.03
0.10
0.02
0.10
0.09
0.09
0.30
0.20
0.03
0.03
0.13
0.03
0.11
0.02
0.17
0.04
0.26
0.02
0.13
0.20
PreC
High
PreC
PreC
PreC
Low
Mod
PreC
PreC
PreC
PreC
PreC
PreC
PreC
PreC
PreC
PreC
Low
PreC
Low
PreC
PreC
PreC
Mod
PreC
PreC
PreC
SpecH
PreC
SpecH
PreC
SpecH
PreC
High
PreC
SpecH
Mod
PreC
SpecH
High
PreC
PreC
High
High
PreC
PreC
High
PreC
SpecH
PreC
High
SpecH
Vpoor
Vpoor
Vpoor
Vpoor
Poor
Vpoor
Vpoor
Poor
Base
Vpoor
Vpoor
Vpoor
Poor
Poor
Vpoor
Poor
Base
Vpoor
Poor
Poor
Poor
Poor
Vpoor
Base
Poor
Poor
Poor
Base
Vpoor
Base
Poor
Base
Base
Base
Vpoor
Base
Base
Vpoor
Base
Base
Vpoor
Vpoor
Base
Base
Base
Poor
Base
Poor
Base
Base
Base
Base
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Vpoor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Vpoor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Poor
Base
Poor
Base
Poor
Base
Base
Vpoor
Base
Base
Poor
Poor
Poor
Base
Poor
Poor
Base
Poor
Base
Poor
Base
Base
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Poor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Poor
Vpoor
Vpoor
Vpoor
Vpoor
Vpoor
Poor
Vpoor
Vpoor
Vpoor
Base
Vpoor
Base
Vpoor
Base
Poor
Vpoor
Base
Poor
Vpoor
Vpoor
Vpoor
Base
Vpoor
Vpoor
Poor
Vpoor
Base
Vpoor
Base
Base
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 7-5a. Example ranking of 52 VA buildings using total Risk Points - building properties
based on Rehabilitated (new building) conditions
Risk Points
Building Name
Deaths
Injuries
Dollar
Loss
Facility
Function
Total
VA
Seis.
W. Los Angeles 500
W. Los Angeles 205
W. Los Angeles 114
San Diego 1
Seattle 100NT
San Francisco 1
San Francisco 6
Portland 100
American Lake 81
Reno 1
Palo Alto 6
San Juan 1
Long Beach 126A
Palo Alto 54
Sepulveda 103
American Lake 61
San Francisco 9
Martinez 5/R-1
Reno 1A
Sepulveda 99
Ft. Harrison 154
Long Beach 138
Portland 6
Seattle 13
Marion 14
Anchorage 3001
White City 232
Roseburg 1
San Diego 2
Boston 1
Columbia 1
Marion 8
New York 1
Roseburg 2
Walla Walla 69
White City 204
Albuquerque 1
N. Little Rock 66
Prescott 107
Columbia 8
Prescott 117
Albuquerque 10
Ft. Harrison 154A
N. Little Rock 69
Nashville 1
Walla Walla 76
Boston 5
East Orange 7
East Orange 8
Montrose 10
Montrose 20
White River Jt. 2
1.7
0.1
0.1
0.3
0.1
0.1
0.1
0.4
0.0
0.1
0.1
0.2
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
9.9
1.6
2.2
3.9
1.9
2.1
2.4
1.6
1.5
1.5
1.8
1.9
1.2
1.2
0.2
0.6
0.4
0.6
0.4
0.6
0.5
0.6
0.3
0.3
0.1
0.6
0.1
0.2
0.1
0.2
0.1
0.1
0.2
0.1
0.1
0.1
0.1
0.1
0.1
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
9.2
6.3
4.7
2.5
4.2
3.9
3.4
2.8
3.2
3.0
1.6
1.3
1.9
1.8
1.6
1.2
1.4
1.0
1.2
0.9
0.9
0.7
0.9
0.9
1.0
0.4
0.9
0.7
0.7
0.3
0.3
0.3
0.1
0.3
0.3
0.3
0.2
0.2
0.2
0.2
0.2
0.1
0.1
0.1
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
20.8
8.0
7.0
6.7
6.2
6.1
5.9
4.8
4.7
4.6
3.5
3.4
3.2
3.0
1.8
1.8
1.8
1.6
1.6
1.5
1.4
1.3
1.2
1.2
1.1
1.0
1.0
0.9
0.8
0.6
0.4
0.4
0.4
0.4
0.4
0.4
0.3
0.3
0.3
0.2
0.2
0.1
0.1
0.1
0.1
0.1
0.0
0.0
0.0
0.0
0.0
0.0
VH
VH
VH
VH
VH
VH
VH
H
H
VH
VH
H
VH
VH
VH
H
VH
VH
VH
VH
MH
VH
H
VH
H
VH
MH
VH
VH
ML
MH
H
MH
VH
MH
MH
MH
MH
ML
MH
ML
MH
MH
MH
ML
MH
ML
MH
MH
ML
ML
ML
7-22
MCE Ground Motions
Te
(sec.)
1.72
0.66
0.61
1.49
2.01
0.79
0.69
2.19
0.73
1.04
0.69
2.00
0.57
0.39
0.25
0.43
0.38
0.27
0.60
0.26
0.66
0.34
0.44
0.46
0.49
0.34
0.41
0.99
0.41
3.35
0.62
0.40
2.37
0.64
0.68
0.41
0.88
0.66
0.66
0.41
0.39
0.38
0.35
0.48
0.85
0.31
0.70
0.50
0.46
0.58
0.58
0.27
SA0.3s SA1.0s
(g)
(g)
2.23
2.23
2.23
1.23
1.47
1.97
1.97
1.05
1.29
1.83
1.82
1.02
1.57
1.82
2.13
1.29
1.97
1.66
1.83
2.13
0.91
1.57
1.05
1.47
1.01
1.50
0.71
0.90
1.23
0.35
0.63
1.01
0.69
0.90
0.57
0.71
0.65
0.54
0.48
0.63
0.48
0.65
0.91
0.54
0.30
0.57
0.35
0.44
0.44
0.41
0.41
0.38
1.24
1.24
1.24
0.72
0.85
1.39
1.39
0.62
0.77
0.93
1.16
0.57
0.88
1.16
1.43
0.77
1.39
0.92
0.93
1.43
0.52
0.88
0.62
0.85
0.70
1.02
0.48
0.60
0.72
0.17
0.33
0.70
0.25
0.60
0.31
0.48
0.32
0.31
0.22
0.33
0.22
0.32
0.52
0.31
0.15
0.31
0.17
0.17
0.17
0.17
0.17
0.20
Building Exposure Data
Occupancy
Value
($M)
ECO
Hospital
Hospital
Research
Hospital
Hospital
Research
Research
Hospital
Hospital
Hospital
Offices
Hospital
Research
Research
Research
Long-Term
Long-Term
Research
Offices
Domiciliary
Hospital
Research
Research
Research
Boiler Plant
Domiciliary
Boiler Plant
Hospital
Boiler Plant
Hospital
Educational
Long-Term
Hospital
Long-Term
Long-Term
Domiciliary
Long-Term
Outpatient
Hospital
Boiler Plant
Outpatient
Research
Outpatient
Boiler Plant
Hospital
Boiler Plant
Boiler Plant
Research
Boiler Plant
Domiciliary
Boiler Plant
Boiler Plant
$1,218
$69
$105
$1,111
$202
$57
$78
$890
$91
$179
$46
$769
$122
$45
$4
$36
$8
$20
$18
$41
$172
$92
$33
$29
$6
$23
$16
$160
$23
$904
$67
$10
$903
$74
$53
$12
$78
$50
$129
$10
$13
$35
$27
$6
$810
$5
$8
$38
$12
$37
$9
$11
2,343
133
350
2,137
388
189
261
1,712
175
345
310
1,478
405
150
12
132
29
66
118
305
331
308
110
97
5
171
13
308
19
1,739
192
36
1,737
270
193
91
285
226
248
8
61
115
123
5
1,557
4
7
126
10
274
8
9
Seismic Risk Assessment of VA Hospital Buildings
Phase I Report- Approach and Methods
April 13, 2010
Table 7-5b. Example ranking of 52 VA buildings using total Risk Points - building properties
based on Rehabilitated (new building) conditions
Risk Points
Performance Data
Building Properties
Building Name
Deaths
Injuries
Dollar
Loss
Facility
Function
Total
Year
Flrs.
W. Los Angeles 500
W. Los Angeles 205
W. Los Angeles 114
San Diego 1
Seattle 100NT
San Francisco 1
San Francisco 6
Portland 100
American Lake 81
Reno 1
Palo Alto 6
San Juan 1
Long Beach 126A
Palo Alto 54
Sepulveda 103
American Lake 61
San Francisco 9
Martinez 5/R-1
Reno 1A
Sepulveda 99
Ft. Harrison 154
Long Beach 138
Portland 6
Seattle 13
Marion 14
Anchorage 3001
White City 232
Roseburg 1
San Diego 2
Boston 1
Columbia 1
Marion 8
New York 1
Roseburg 2
Walla Walla 69
White City 204
Albuquerque 1
N. Little Rock 66
Prescott 107
Columbia 8
Prescott 117
Albuquerque 10
Ft. Harrison 154A
N. Little Rock 69
Nashville 1
Walla Walla 76
Boston 5
East Orange 7
East Orange 8
Montrose 10
Montrose 20
White River Jt. 2
1.7
0.1
0.1
0.3
0.1
0.1
0.1
0.4
0.0
0.1
0.1
0.2
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
9.9
1.6
2.2
3.9
1.9
2.1
2.4
1.6
1.5
1.5
1.8
1.9
1.2
1.2
0.2
0.6
0.4
0.6
0.4
0.6
0.5
0.6
0.3
0.3
0.1
0.6
0.1
0.2
0.1
0.2
0.1
0.1
0.2
0.1
0.1
0.1
0.1
0.1
0.1
0.0
0.0
0.0
0.0
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
0.0
9.2
6.3
4.7
2.5
4.2
3.9
3.4
2.8
3.2
3.0
1.6
1.3
1.9
1.8
1.6
1.2
1.4
1.0
1.2
0.9
0.9
0.7
0.9
0.9
1.0
0.4
0.9
0.7
0.7
0.3
0.3
0.3
0.1
0.3
0.3
0.3
0.2
0.2
0.2
0.2
0.2
0.1
0.1
0.1
0.0
0.1
0.0
0.0
0.0
0.0
0.0
0.0
20.8
8.0
7.0
6.7
6.2
6.1
5.9
4.8
4.7
4.6
3.5
3.4
3.2
3.0
1.8
1.8
1.8
1.6
1.6
1.5
1.4
1.3
1.2
1.2
1.1
1.0
1.0
0.9
0.8
0.6
0.4
0.4
0.4
0.4
0.4
0.4
0.3
0.3
0.3
0.2
0.2
0.1
0.1
0.1
0.1
0.1
0.0
0.0
0.0
0.0
0.0
0.0
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
2006
7
3
3
6
8
4
4
9
4
7
3
11
3
2
1
2
2
1
3
1
4
2
3
2
1
1
2
5
1
14
3
2
19
3
2
2
5
3
4
1
1
2
1
1
4
1
1
2
1
3
1
1
7-23
MBT
Te
(sec.)
Cs
SDL
STR
NSD
NSA
(CON)
S2
C2
C2
S2
S2
C2
C2
S2
C2
C2
C2
C2
C2
C2
RM1
C2
C2
S3
C2
RM1
C2
C2
C2
RM2
C2
W1
RM1
C2
C2
C1
C2
C2
C2
C2
RM1
RM1
C2
C2
C2
C2
S1
C2
C2
RM1
C2
RM1
C2
C2
C2
C2
C2
C2
1.72
0.54
0.51
1.49
1.76
0.65
0.57
2.05
0.60
0.86
0.61
2.00
0.57
0.39
0.25
0.43
0.31
0.27
0.60
0.26
0.58
0.34
0.44
0.43
0.40
0.34
0.36
0.81
0.39
3.35
0.55
0.33
2.09
0.52
0.60
0.36
0.77
0.58
0.62
0.36
0.37
0.34
0.35
0.42
0.80
0.31
0.66
0.44
0.40
0.55
0.55
0.26
0.18
0.37
0.37
0.10
0.10
0.33
0.33
0.07
0.22
0.19
0.30
0.09
0.30
0.30
0.35
0.22
0.33
0.28
0.31
0.35
0.15
0.26
0.18
0.24
0.17
0.25
0.12
0.13
0.20
0.01
0.11
0.17
0.02
0.15
0.10
0.12
0.08
0.09
0.11
0.11
0.08
0.11
0.15
0.09
0.04
0.10
0.05
0.07
0.07
0.06
0.06
0.06
SpecH
SpecH
SpecH
SpecH
SpecH
SpecH
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High
High
SpecH
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Mod
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Seismic Risk Assessment of VA Hospital Buildings
Phase I Report - Approach and Methods
April 13, 2010
CHAPTER 8. CONCLUSION
This chapter provides a summary of the seismic risk assessment technology developed for the
Department of Veteran Affairs (VA), discusses limitations on applications of the technology, and
suggests additional studies to improve certain data or methods of the technology.
8.1
Summary
The HAZUS-based technology developed for the VA provides a powerful tool for seismic risk
assessment of buildings in the VA building inventory. The technology can be used to evaluate
the seismic risk of a single building, a number of buildings at a specific medical center, a larger
number of buildings in an entire region, and an even larger number of buildings within an entire
region (VISN). Such assessments will allow the VA to compare relative risks presented on a
building by building basis, which should be useful in planning for future funding of seismic
upgrade projects, and in planning for post-earthquake response.
The seismic risk assessment technology calculates the probability of building damage including
likelihood of collapse of the structural system. The technology also determines expected values
of loss, including the number of casualties (i.e., immediate deaths, life-threatening injuries and
injuries requiring hospitalization, respectively), economic losses (due to damage to structural and
nonstructural systems, and components, respectively), and loss of function (likely number of
days of "downtime").
The technology evaluates damage-state probabilities and expected values of loss for two levels
of earthquake ground motion corresponding to design earthquake (Design) and maximum
considered earthquake (MCE) ground motions, respectively, as defined by the site-specific
seismic criteria of ASCE 7-10. Damage-state probabilities and expected values of loss are a
function of the level of ground motion used in the evaluation, and represent the likely amount of
damage or loss if the associated level of ground shaking occurs at the facility site of interest.
As described in the 2009 NEHRP Provisions (parent document of ASCE 7-10), the intent of
seismic codes is to provide reasonable assurance of seismic performance that meets the
following objectives:
•
Avoid serious injury and life loss
•
Avoid loss of function in critical facilities (such as medical centers)
•
Minimize nonstructural repair costs (where practical to do so)
And that these objectives are addressed by:
•
Avoiding structural collapse in very rare, extreme ground shaking
•
Limiting damage to structural and nonstructural systems that could lead to injury,
economic loss or loss of functions for smaller more frequent ground motions.
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Expected casualty losses due to MCE ground motions are particularly meaningful when
considering the Code life-safety objective, stated above - i.e., avoid structural collapse in very
rare, extreme ground shaking, since MCE ground motions represent very rare, extreme ground
shaking. In contrast, damage and associated expected loss of function due to Design ground
motions are more appropriate for comparison with the functionality objectives, stated above i.e., limiting damage for smaller more frequent ground motions, since Design ground motions are
smaller (i.e., two-thirds of MCE ground motions). Arguably, other more appropriate definitions
of smaller, more frequent ground motions could be used to evaluate seismic risk due loss of
function.
While appropriate for casualty and functional losses, Code (Design or MCE) ground motions are
not well suited for comparing economic risk at sites with very different levels of seismicity.
Code ground motions are much more likely to occur at sites of high seismicity (e.g., coastal
California sites) than at sites of lower seismicity (e.g., central and eastern United States sites).
While it makes sense to protect life-safety for rare ground motions, regardless of their frequency
of occurrence, it would not make sense to invest significant amounts of money to avoid
economic losses that could only occur very infrequently.
Accordingly, the seismic risk assessment technology estimates values of average annualized loss
(AAL) that consider both the degree of damage and loss that would result from various levels of
ground motion, as well as the likelihood or frequency of occurrence, of these ground motions
(i.e., so-called Probabilistic ground motions). All else equal, facilities in regions of high
seismicity will have much greater estimates of AAL than those located in regions of low
seismicity. AAL estimates are appropriate for addressing economic losses, particularly when
comparing such losses with the costs of remedial action.
The seismic risk assessment technology is implemented in the Risk Calculation Tool (RCT), an
Excel spreadsheet that allows the user to develop a portfolio of buildings (by entering facility,
building and ground motions data, respectively), to select either an individual building, or group
of buildings from the portfolio, and to evaluate risk for either Code (Design or MCE) or
Probabilistic ground motions, respectively. For each ground motion level, the RCT calculates
peak building response, the probability of structural and nonstructural (and contents) damage
corresponding to this level of response, and the expected values of casualty, functional and
economic losses associated with each type of related building damage.
The RCT uses a "risk point" scheme to evaluate the relative risk of casualty, functional and
economic losses, respectively. Risk points provide a basis for comparison of the seismic risk of
different buildings and to rank buildings from highest risk to lowest risk. For the initial study of
the 52 buildings in the scope of this project (Phase II report), the RCT has been populated with
all necessary facility, building and ground motions data.
8.2
Limitations on Application
The HAZUS-based technology developed for the VA is a state-of-the-art technology that
provides a consistent, technically defendable and comprehensive approach to seismic risk
assessment. The technology is a powerful tool for performing a wide variety of assessments that
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can be of great benefit to the VA for planning of future expenditures, post-earthquake response,
and various other items. While the technology provides a powerful tool for seismic risk
evaluation, the user should be aware of certain inherent limitations on the use of the technology
(and on loss estimation methods, in general).
Expected values of loss (e.g., expected number deaths, expected cost of repair, etc.) represent a
"best estimate" (center) of a range of actual losses that could occur due to the ground motion
level of interest. The range of actual losses is due to uncertainties associated with ground
motions (e.g., frequency content and duration of ground shaking), building data (e.g., number of
people actually in the building at the time of earthquake), building properties (e.g., actual
building strength), and loss rates (e.g., actual costs to repair damaged elements, or replace the
building). Some sources of uncertainty, such as building strength, can be reduced by additional
building analysis and study; others, such as ground motions, can not.
In general, the technology is best suited for comparison of seismic risk between buildings and
facilities, and across regions. Users of the technology are cautioned not to expect that any one
parameter can be estimated with exceptional accuracy. However, while accuracy of any one
parameter may be limited, trends in expected values are still expected to be valid, on average,
and can used to rank the relative risk of the portfolio of buildings.
The seismic risk assessment technology may be used to guide the decision to pursue a building
retrofit or replacement project. Risk results provide valuable information for making decisions
and comparing alternative strategies. However, project budgets are best developed as the result
of a detailed, multi-disciplinary study that addresses all building systems, functional impacts, and
a host of other issues related to the specific characteristics of a building that are generally beyond
the scope of the technology. This is the same approach that the VA has followed during the last
15 years of its’ seismic program.
The level of accuracy and reliability of results of seismic risk assessment are directly related to
the level of detail in the information provided for use in developing building parameters (e.g.,
level of ASCE 31 evaluation). While the technology can be applied with minimal data that
resides in the VA building database (location, age, size, building type, e.g.), it is recommended
that future use of the technology by the VA be done with at least ASCE 31 Tier 1 data, and it is
highly recommended that Tier 2 data be used whenever possible.
Without at least Tier 1 data, the technology should only be used as a screening tool, and include
bounding analyses to estimate “best” and “worst” case scenarios. Further, nonstructural
component behavior would be best addressed by additional evaluation that exceeds the checklist
approach of ASCE 31.
Seismic risk assessment methods are highly technical in nature and implementation of the RCT
is best performed by a structural engineer experienced in seismic evaluation and risk methods.
The number of assumptions and parameters included in the technology makes it difficult for nontechnical users to verify the accuracy of specific results, especially as they relate to casualties,
dollar loss amounts and projected days of loss of function.
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April 13, 2010
Future Studies and Improvements
During development of the seismic risk assessment technology, the NIBS Oversight Committee
suggested a number of topics or areas of potential improvement to HAZUS-based methods or
earthquake data that could not be addressed in the current scope, but should be considered for
future study. These topics are summarized below. Additionally, the Phase II report recommends
future applications of the technology to investigate seismic risk for other VA buildings (than the
52 of this study), including studies of facility seismic risk (i.e., all buildings at a given facility),
or regional seismic risk (i.e., all buildings in a given VISN).
It is recommended that future studies be performed to improve certain data and seismic risk
assessment methods of the HAZUS-based technology, including the following.
•
Ground Motion Data - General. The technology currently includes ground motion data
for the 28 facility sites associated with the 52 buildings in the scope of this study. It is
recommended that additional ground motion data be developed for evaluation of
buildings at other (all) VA facility sites of interest.
•
Ground Motion Data - Deterministic Ground Motions. The technology currently includes
Code (Design and MCE) and Probabilistic ground motions (for 28 facility sites).
Functional losses are now based on Design ground motions, although these ground
motions may not best represent ground shaking most likely to occur at the site of interest.
Alternatively, it is recommended that "deterministic" ground motions be developed and
used for evaluation of functional losses. Deterministic ground motions should be based
on the median (and 84th percentile) response due to the characteristic event on the source
(fault system) that governs hazard at the site of interest (most likely earthquake).
•
Ground Motion Data - Scenario Earthquake Ground Motions. For regional and local
emergency response and recovery planning, it is recommended that "scenario earthquake"
ground motions be developed for selected regions of study. Scenario earthquake are
similar to (median and 84th percentile) deterministic earthquake ground motions, only
they would be based on the same fault system (of the scenario earthquake), rather than on
different fault systems (that govern hazard at the facility site of interest).
•
Earthquake Shaking Duration - Magnitude and fault distance data are not currently
available and the technology relies on default values of the "Kappa" factor to account for
the effects shaking duration. Shaking duration is very important to damage and loss
estimates and it is recommended that magnitude and fault distance data be developed for
each site of interest.
•
Site Class Data - Site class (soil type) data are not known for certain facility sites and the
technology assumes default Site Class D when determining building response. Since
building response and the associated amount of damage can be significantly affected by
the site characteristics, it is recommended that future studies ensure that site conditions
are known.
•
Ground Failure (Liquefaction) - The technology does not include methods for assessing
risk due to ground failure (liquefaction). While generally less critical than ground
shaking, ground failure can significantly affect building risk and it is recommended that
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future studies ensure that the local conditions, including the propensity for ground failure
(liquefaction) be known.
•
Improved Nonstructural System Data - Because of the importance of nonstructural
system and element performance on dollar losses and downtime (especially in the short
term), it is recommended that future studies be performed to generate improved
nonstructural methods and data for seismic risk assessment that go into more detail than
the simple checklist characterization required by ASCE 31.
•
Loss of Function - The HAZUS-based methods do not consider building size in the
estimation of loss of function (i.e., time required to restore functionality). Since it is
likely that it will take significantly longer to restore larger buildings to functionality (due
to more locations of damage, resource limitations, etc.), it is recommended that improved
methods be developed for estimating loss of function that consider building size.
•
Default Building Data - While ASCE 31 Tier1, or better, data are recommended for
establishing building properties, large scale risk studies (e.g., all VA buildings in a given
region) would require use of "default" data for those buildings that have not had an ASCE
31 evaluation. It is recommended that procedures and bounding values of default data be
developed for seismic risk assessment when Tier 1 (or better) data are not available.
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CHAPTER 9. REFERENCES
ASCE, 2003. Seismic Evaluation of Existing Buildings. American Society of Civil Engineers
Standard ASCE/SEI 31-03. (Reston, VA: ASCE).
ASCE, 2005. Minimum Design Loads for Buildings and Other Structures. American Society of
Civil Engineers Standard ASCE/SEI 7-05. (Reston, VA: ASCE).
ASCE, 2006. Seismic Rehabilitation of Existing Buildings. American Society of Civil Engineers
Standard ASCE/SEI 41-06. (Reston, VA: ASCE).
ASCE, 2010. Minimum Design Loads for Buildings and Other Structures. American Society of
Civil Engineers Standard ASCE/SEI 7-10. (Reston, VA: ASCE).
ATC, 2009. Guidelines for Seismic Performance Assessment of Buildings. Applied Technology
Council, ATC-58, 50% Draft, prepared for the Federal Emergency Management Agency.
(Redwood City, CA. ATC).
Degenkolb, 2001. "Department of Veterans Affairs, Seismic Inventory, Phase 3, Roseburg,
Building 1," prepared for Office of Facilities Management, Department of Veteran
Affairs, Washington, DC, prepared by Degenkolb Engineers, August 30, 2001, Job No.
97472.02. (copy included as Appendix B).
Degenkolb, 2005. "Department of Veterans Affairs, Seismic Inventory, Phase 6, Prescott,
Building 107," prepared for Office of Facilities Management, Department of Veteran
Affairs, Washington, DC, prepared by Degenkolb Engineers, August 2005, Job No.
97472.06. (copy included as Appendix C).
DVA, 2006. Seismic Design Requirements. Department of Veterans Affairs (DVA), Office of
Facilities Management, Strategic Management Office, H-18-8, July 2006. (Washington,
D.C.: DVA).
FEMA, 1992. NEHRP Handbook for the Seismic Evaluation of Existing Buildings. Federal
Emergency Management Agency, FEMA 178. (Washington, D.C.: FEMA).
FEMA, 2000. Prestandard and Commentary for the Seismic Rehabilitation of Buildings.
Federal Emergency Management Agency, FEMA 356. (Washington, D.C.: FEMA).
FEMA, 2009. Quantification of Building Seismic Performance Factors. Federal Emergency
Management Agency, FEMA P695. (Washington, D.C.: FEMA).
Kircher, C., W. Holmes, R. Whitman, 2006. HAZUS Earthquake Loss Estimation Methods,” Natural
Hazards Review. (Washington, D.C.: American Society of Civil Engineers).
Luco, Nico, 2006. "VAhazard(Rev091217).xlsx" (private communication).
NIBS, 2002. Earthquake Loss Estimation Methodology, HAZUS99-SR2, Advanced Engineering
Building Module, Technical and User’s Manual, prepared by National Institute of
Building Sciences (NIBS) for the Federal Emergency Management Agency.
(Washington, D.C.: NIBS).
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NIBS, 2006. Multi-hazard Loss Estimation Methodology: Earthquake Model, HAZUS-MH MR2
Technical Manual, prepared by the National Institute of Building Sciences (NIBS) for the
Federal Emergency Management Agency. (Washington, D.C.: NIBS).
OSHPD, 2007. "Express Terms for Proposed Building Standards of the Office of State wide
Health Planning and Development Regarding proposed changes to the California
Building Standards Administrative Code, California Code of Regulations, Title 24, Part
1," Title 24, Part 1, Chapter 6 "Seismic Evaluation Procedures for Hospital Buildings."
(copy included as Appendix A of this report).
USGS website (ASCE 7-05 data). http://earthquake.usgs.gov/designmaps/usapp/buildings)
USGS website (ASCE 7-10 data). http://earthquake.usgs.gov/designmaps/usapp/.
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CHAPTER 10. GLOSSARY
BUILDING CLASSIFICATION:
Model Building Type (MBT): Standardized structural system types based on the
classification scheme of ASCE 31/HAZUS (FEMA 178), summarized below:
C1
Reinforced-concrete moment frame buildings
C2
Reinforced-concrete moment frame buildings
C3
Reinforced-concrete moment frame buildings
PC1
Precast concrete buildings with tilt-up walls
PC2
Precast concrete frame bulldogs with concrete shear walls
S1
Steel moment frame buildings
S2
Steel braced frame buildings
S3
Steel light frame buildings
S4
Steel frame buildings with cast-in-placer concrete shear walls
S5
Steel frame buildings with masonry infill walls
RM1 Reinforce-masonry bearing wall buildings with wood or metal diaphragms
RM2 Reinforce-masonry bearing wall buildings with precast concrete
diaphragms
URM Unreinforced masonry bearing wall building
W1
Wood light frame buildings
W2
Wood buildings (greater than 5,000 sq. ft.)
MH
Manufactured housing
Occupancy: Primary use of building based on critical and essential, and ancillary facility
types of Table 1 of DVA H-18-08, as described in Table 2-4.
BUILDING OCCUPANTS:
Peak Occupants (Peak): Maximum number of occupants in the building at any time.
Effective Continuous Occupants (ECO): Average number of occupants in building
over time, considering peak, after-hour and weekend use of building.
BUILDING SYSTEMS:
Structural System (STR): Foundation and structural elements supporting gravity loads,
lateral (earthquake) loads and other loads.
Nonstructural Drift-Sensitive Systems (NSD): Nonstructural systems and components
sensitive to damage due to building drift response (e.g., partitions, facades, etc.).
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Nonstructural Acceleration-Sensitive Systems (NSA): Nonstructural systems and
components sensitive to damage due to building acceleration response (e.g.,
suspended ceilings, lights, mechanical equipment, etc.).
Contents (CON): Contents of building sensitive to damage due to building acceleration
response (e.g., furnishings, medical equipment, etc.).
BUILDING DATA QUALITY RATING - Data quality rating scheme used to adjust fragility
curve uncertainty to reflect confidence in the building data obtained from ASCE 31
building evaluations:
Best - Very high confidence in damage/loss parameters (Tier 3 analysis - NDA).
Very Good - High confidence in damage/loss parameters (Tier 3 analysis).
Good - Average confidence in damage/loss parameters (Tier 2 analysis).
Poor - Low confidence in damage/loss parameters (Tier 1 analysis).
Very Poor - Very Low confidence in damage/loss parameters (i.e., no investigation).
BUILDING RESPONSE: Peak lateral displacement (drift) response or peak floor acceleration
response of the building due to a given intensity of earthquake ground motions.
BUILDING DAMAGE: Discrete states of physical damage to the structure, nonstructural
systems and contents, respectively, due to building response:
Slight - Minor damage not affecting building function and of modest cost to repair (0% 5%), if repair is required (likely Green Tag).
Moderate - Significant damage requiring repair (5% - 25%), but not likely to require
more than temporary closure of the building (likely Green Tag).
Extensive - Significant damage requiring repair (25% - 75%) and affecting building
function, possibly requiring closure until repairs are made (likely Yellow tag).
Complete - Heavy damage requiring repair (75% - 100%) or demolition, building closed
until repairs are made (likely Red tag).
Collapse - Partial or full collapse of the building characterized by the fraction of a
building with Complete structural damage that is expected to also be collapsed.
BUILDING LOSS: Casualty, economic and functional losses due to building damage:
Casualty Losses: Immediate deaths, life-threatening injuries requiring immediate
rescue, serious injuries requiring hospitalization, and minor injuries (treat and
release) due to structural damage, primarily building Collapse.
Direct Economic (Dollar) Losses: Costs of repair (or replacement) of damage to the
structure, nonstructural systems and contents, respectively.
Loss of Function: Time required to restore building to service.
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SEISMIC DESIGN LEVEL (SDL) - HAZUS classification of the building seismic design
related to the regional seismicity, as defined by the DVA H-18-08 and building design
vintage (see Table 2-7):
Special High (SpecH) - Buildings in regions of Very High (VH) seismicity and modern
(post-1975) design vintage.
High - Buildings in regions of High (H) seismicity and modern design vintage.
Moderate (Mod) - Buildings in regions of Moderate-High (MH) seismicity and modern
design vintage or older design vintages in regions of High seismicity.
Low - Buildings in regions of Moderate-Low (ML) seismicity and modern design vintage
or older design vintages in other regions of seismicity.
Pre-Code (PreC) - Buildings in regions of Low (L) seismicity and modern design
vintage or older design vintages in other regions of seismicity. Pre-Code
represents buildings not designed for earthquake loads
SEISMIC PERFORMANCE RATING - Generic rating of anticipated seismic performance of
the structural system (as defined Table 2-8), nonstructural drift-sensitive systems (as
defined in Table 2-9), and nonstructural acceleration-sensitive systems and contents (as
defined in Table 2-10), as summarized below:
Baseline (Base) - Low risk of structural collapse (MCE ground motions); good (2%) drift
capacity of NSD components; NSA components generally braced and anchored.
Poor - Moderate/high risk of structural collapse (MCE ground motions), limited (1%)
drift capacity of NSD components; NSA components partially braced and
anchored.
Very Poor (VPoor) - Very high risk of structural collapse (MCE ground motions), very
limited (0.5%) drift capacity of NSD components; little or no bracing and
anchorage of NSA components.
STRUCTURAL DEFICIENCY RATING - Rating of specific HAZUS parameters related to
building capacity, response and damage (fragility), and casualty loss (collapse factor),
respectively, as described in Tables 2-11a - 2-11c:
Baseline (Base) - No significant structural deficiencies (default values of HAZUS)
Sub-Baseline (SubB) - At least one significant structural deficiency
Ultra-sub-Baseline (USB) - Certain combinations of multiple significant structural
deficiencies.
SITE CLASS: Classification of the facility site based on the type of soil (ASCE 7):
Site Class A
Hard rock
Site Class B
Rock
Site Class C
Very dense soil and soft rock
Site Class D
Stiff Soil
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Site Class E
Soft clay soil
Site Class F
Soils requiring site response analysis
EARTHQUAKE:
Fault Distance: Closest distance between the site of interest and fault rupture plane.
Hazard: Earthquake ground motions or ground failure (e.g., liquefaction).
Intensity: Level or strength of earthquake ground motions at a specific location.
Magnitude: Size of earthquake related to the amount of energy released.
Duration: Duration of earthquake ground motions related to the earthquake magnitude
and fault distance.
EARTHQUAKE GROUND MOTIONS: Ground shaking characterized by peak ground
acceleration (PGA) and short-period and 1-second response spectral acceleration (i.e.,
response spectra used in building codes) for different definitions of earthquake intensity:
Code Ground Motions: Two intensities corresponding to design earthquake and
maximum considered earthquake (MCE) ground motions, as defined by ASCE 7.
Probabilistic Ground Motions: Ten intensities of ground motions, corresponding to
return periods ranging from 10 years (very likely) to 10,000 years (very rare), as
defined by the current ground motion hazard functions of the USGS.
STATISTICAL-BASED TERMS:
Average Annualized Loss (AAL): Risk measure of the loss parameter of interest
defined as average loss in a 1-year period due to all possible ground motion
intensities characterized by ground motion hazard functions.
Expected Loss: Risk measure based on the expected value of the loss parameter of
interest for a given intensity of ground motions.
Fragility Function: Function relating the probability of building damage to building
response.
Hazard Function: Function describing the annual frequency of the hazard of interest
(e.g., ground motions).
Loss Function: Function relating the probability of building loss to building damage.
Return Period (years): The inverse of the annual frequency of the hazard of interest
(e.g., ground motions).
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