Preparation of New Seismic
Design Maps for Building Codes
2009 COSMOS Technical Session
Reprinted
p
with Permission from EERI
EERI Seminar on Next Generation Attenuation Models
Nicolas Luco, Research Structural Engineer
USGS Golden,
USGS,
Golden Colorado
Acknowledgements
• USGS Hazard Mapping Project, particularly …
– Mark Petersen (Project Chief)
– Steve Harmsen (Modeler)
– Ken Rukstales (GIS)
– Eric Martinez (Web)
– Greg Smoczyk (DB)
– Sean McGowan (QA)
• FEMA-Funded BSSC Project ‘07
– Charlie Kircher (Chair)
– See seminar presentation by Kircher for member list
• ASCE 7 SSC Ad-Hoc Ground Motion Committee
– Charlie Kircher (Chair)
– John Hooper (SSC Chair)
– C.B. Crouse (TC1 Chair)
– Jim Harris (ASCE 7 MC)
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
New ASCE 7-10 “Design Maps”
FIGURE 22-1 MAXIMUM CONSIDERED EARTHQUAKE (MCER) GROUND MOTION OF 0.2 SEC
SPECTRAL RESPONSE ACCELERATION (5% OF CRITICAL DAMPING),
DAMPING) SITE CLASS B
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Outline of Presentation
• Preparation of new design maps using …
– Seismic hazard computed by USGS
• Probabilistic hazard curves
• Deterministic median ground motions
– Procedures developed by Project ‘07
• Sti
Stipulated
l t d iin site-specific
it
ifi procedures
d
(Ch
(Ch. 21) off
ASCE 7-10 & 2009 NEHRP Provisions
• D
Design
i maps web
b application
li ti and
d other
th
associated products prepared by USGS
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Preparation of New Design Maps
• Consistent with site-specific procedures
(Ch. 21) of ASCE 7-10 & 2009 NEHRP …
– Probabilistic ground motion
• Method 1: Uniform-hazard GM x Risk Coefficient
• Method 2: Risk-targeted probabilistic GM directly
– Deterministic ground motion
• 84th-%ile GM, but not < 1.5Fa or 0.6Fv / T
– MCER GM = min( Prob. GM, Det. GM)
– All GMs are max-direction spectral accel.’s
• Ground motions computed
p
by
y USGS
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Probabilistic Ground Motions
From site-specific procedures (Chapter 21)
of ASCE 7-10 & 2009 NEHRP Provisions …
21.2.1, Probabilistic Ground Motion: The probabilistic spectral response
accelerations shall be taken as the spectral response accelerations in the direction of
maximum horizontal response
p
represented
p
byy a 5 p
percent damped
p
acceleration
response spectrum that is expected to achieve a 1 percent probability of collapse
Probabilistic
within
a 50-yr. period. Ground Motion = Risk-Targeted GM
21.2.1.2,
21
2 1 2 Method 2: At each spectral response period for which the acceleration is computed,
computed
ordinates of the probabilistic ground motion response spectrum shall be determined from iterative
integration of a site-specific hazard curve with a lognormal probability density function
representing the collapse fragility (i.e., probability of collapse as a function of spectral response
acceleration) The ordinate of the probabilistic ground
acceleration).
ground-motion
motion response spectrum at each period
shall achieve a 1 percent probability of collapse within a 50-yr. period for a collapse fragility
having (i) a 10 percent probability of collapse at said ordinate of the probabilistic ground-motion
response spectrum and (ii) a logarithmic standard deviation values of 0.6.
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk-Targeted Ground Motions
Calculated iteratively by combining …
Risk Target
defined by Project ‘07
Building Fragility Curves
defined b
by Project ‘07
GM Hazard Curves
(e g from USGS)
(e.g.,
Prob.
ob of
o Collapse
Co apse
in 50 yrs = 1%
… via “Risk Integral” (e.g. ATC 3-06), i.e., …
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Forr a giv
ven loc
cation …
Risk-Targeted Ground Motions
“Guess” RTGM
Generate fragility curve as a function of RTGM
Integrate fragility & hazard curves to calculate risk
P[Collapse] in 50yrs
= 1%?
No
Yes
RTGM Calculated
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk-Targeted GMs – Example
GM hazard curves from USGS …
Notes:
The SA values from USGS
have been factored by
1.1 for 0.2s or 1.3 for 1.0s
to convert (approximately)
to max direction.
Conventional “2500-yr” GMs
are interpolated from such
hazard curves.
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk-Targeted GMs – Example
Generic fragility curves assuming, for our
1st iteration, that RTGMs = …
Generic fragility curve equation: where EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk-Targeted GMs – Example
Risk Integration:
Risk
Fragility
Hazard
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Ris
sk
Fragility
y
Risk Integration:
Ha
azard
Risk-Targeted GMs – Example
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Ris
sk
Fragility
y
Risk Integration:
Ha
azard
Risk-Targeted GMs – Example
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk-Targeted GM (RTGM) Maps
These intermediate (to MCER GM) maps are
not
ot included
c uded in ASCE
SC 7-10
0o
or 2009
009 NEHRP
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk-Targeted Ground Motions
From site-specific procedures (Chapter 21)
of ASCE 7-10 & 2009 NEHRP Provisions …
21.2.1, Probabilistic Ground Motion: The probabilistic spectral response
accelerations shall be taken as the spectral response accelerations in the direction of
maximum horizontal response
p
represented
p
byy a 5 p
percent damped
p
acceleration
response spectrum that is expected to achieve a 1 percent probability of collapse
Probabilistic
within
a 50-yr. period. Ground Motion = Risk-Targeted GM
21.2.1.1,
21
2 1 1 Method 1: At each spectral response period for which the acceleration is
computed, ordinates of the probabilistic ground motion response spectrum shall be
Risk-Targeted
GM
determined as the product
of the risk coefficient,
CR, =
and the spectral response
acceleration from aUniform-Hazard
5 percent damped acceleration
response
spectrum having a 2
((2500-yr)
y ) GM
percent probability of exceedance within a 50-yr. period. The value of the risk
x Risk
Coefficient
coefficient, CR, shall be determined
using
values of CRS and CR1 from Figs. 22-3 and
22-4, respectively. …
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk Coefficients (CR’s)
• Conventional uniform-hazard (2500-yr)
GMs interpolated from hazard curves
Risk-Targeted GMs
• CR’s
s=
Uniform-Hazard GMs
• e.g.,
SFBA Location
MMA Location
Risk-Targeted GM
1.38g
0.96g
Uniform Hazard GM
Uniform-Hazard
1 29g
1.29g
1 18g
1.18g
Risk Coefficient (CR)
1.07
0.82
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk Coefficient (CR) Maps
These intermediate maps are included
in ASCE
SC 7-10
0 ((for
o Ch.
C 21)) a
and
d 2009
009 NEHRP
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk Coefficient (CR) Maps
50 °
N
45 °
N
40 °
N
35 °
N
30 °
N
25 °
N
125 °
W
0.7
° W
120 °
W
115 ° W
0.8
110 ° W
0.9
105° W
1
100° W
1.1
90° W
95° W
1.2
8 5° W
°
80 W
1.3
1.4
°
75 W
7
1.5
°
0 W
65
1.6
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk Coefficient (CR) Maps
50 °
N
45 °
N
40 °
N
35 °
N
30 °
N
25 °
N
125 °
W
° W
120 °
W
115 ° W
110 ° W
105° W
< 0.85
0.7
0.8
0.9
1
100° W
1.1
90° W
95° W
1.2
8 5° W
°
80 W
1.3
1.4
°
75 W
7
1.5
°
0 W
65
1.6
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Risk Coefficient (CR) Maps
50 °
N
45 °
N
40 °
N
35 °
N
30 °
N
25 °
N
125 °
W
0.7
° W
120 °
W
115 ° W
0.8
110 ° W
0.9
105° W
1
100° W
1.1
90° W
95° W
1.2
8 5° W
°
80 W
°
75 W
7
°
0 W
65
> 1.15
1.3
1.4
1.5
1.6
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Summary: Probabilistic GMs
• Probabilistic GMs = Risk-Targeted GMs
• Risk-Targeted
g
GMs calculated from …
– GM hazard curves (from USGS)
– Building fragility curves (def
(def. by Project ’07)
07)
– Risk target (defined by Project ‘07)
Risk-Targeted
Risk
Targeted GMs
• Risk Coefficients =
Uniform-Hazard GMs
• Risk Coeff. Maps included in ASCE 7-10
for combination with site-specific UHGMs
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Deterministic Ground Motions
From site-specific procedures (Chapter 21)
of ASCE 7-10 & 2009 NEHRP Provisions …
21.2.2, Deterministic Ground Motion: The deterministic spectral response
acceleration at each period shall be calculated as an 84th-percentile 5 percent damped
spectral response acceleration in the direction of maximum horizontal response
computed at that period. … the ordinates of the deterministic ground motions response
Deterministic GM =
spectrum shall not be taken as lower than the corresponding ordinates of the response
spectrum determined
withGM,
Fig. ,21.2-1,
max(in( accordance
84th-%ile
1.5F…a ) for 0.2s
max( 84th-%ile GM, 0.6Fv ) for 1.0s
(a max-direction
max direction GM, like Probabilistic GM is)
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Median Ground Motions
As presented by Petersen, USGS produces
median (50th-%ile) GMs maps, e.g., …
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Deterministic Ground Motions
• As decided by Project ‘07 …
– 84th-%ile
%ile GMs ≈ 1.8
1 8 x Median GMs
– For max-direction GMs, also factor by …
•1
1.1
1 ffor 0
0.2s
2
• 1.3 for 1.0s
• Since Fa=1 and Fv=1 for Site Class B, …
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Deterministic Maps
These intermediate maps are not included
in ASCE
SC 7-10
0 but a
are
e in 2009
009 NEHRP
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
MCER Ground Motions
From site-specific procedures (Chapter 21)
of ASCE 7-10 & 2009 NEHRP Provisions …
21.2.3, Site-Specific MCER: The site-specific MCER spectral response acceleration at
any period, SaM, shall be taken as the lesser of the spectral response accelerations
MCE
min
Prob
Prob.
GM,
Det.
Det
f
from
th probabilistic
the
b bili tiR GM
ground
d=
motions
ti
of(f Section
S
ti
21GM
21.2.1
2 1 and
d the
th deterministic
dGM
t
i )i ti ground
d
motions of Section 21.2.2.
Recall …
Recall,
– Prob. GM = Risk-Targeted GM
– Det. GM
G = max(( 84th-%ile
% GM,
G 1.5Fa or 0.6Fv / T))
– Both are max-direction GMs
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Preparation of New Design Maps
Probabilistic GMs
(Risk-Targeted)
Deterministic GMs
New MCER GMs
To relate back
to conventional
uniform-hazard
(2500-yr) GMs …
Risk Coefficients
Uniform-Hazard GMs
X
─ In ASCE 7-10
─ In 2009 NEHRP
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Outline of Presentation
• Preparation of new design maps using …
– Seismic hazard computed by USGS
• Probabilistic hazard curves
• Deterministic median ground motions
– Procedures developed by Project ‘07
• Sti
Stipulated
l t d iin site-specific
it
ifi procedures
d
(Ch
(Ch. 21) off
ASCE 7-10 & 2009 NEHRP Provisions
• D
Design
i maps web
b application
li ti and
d other
th
associated products prepared by USGS
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
http://earthquake.usgs.gov/designmaps/usapp
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Other USGS Design Map Products
• Posters of design GMs (SDS & SD1) and
Seismic Design Categories (SDCs)
– For Site Classes A-E, Occ. Categories I-III, IV
– Cross-check for Design Maps Web App
– Also available as Google Earth/Maps KMLs
• International Residential Code (IRC) SDC
map consistent with ASCE 7-10
• Plans for (a) risk coefficient calculator, &
(b) TL, PGAM, & SDC in new web app
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
COSMOS Summary
• New site-specific procedures of ASCE7-10
parallel preparation of new design maps
• Design maps = application of site-specific
procedures for VS30=760m/s ((Site Class B))
p
• Like in ASCE 7-05, new site-specific
procedures entail PSHA and DSHA
• Unlike in ASCE 7-05, new procedures
involve iterative risk integration (of hazard
& fragility curves) or USGS CR maps
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009
Questions?
nluco@usgs.gov
( 303 ) 273 - 8683
EERI Seminar on Next Generation Attenuation Models
“Preparation of New Seismic Design Maps for Building Codes,” N. Luco, USGS
September, 2009