SEVERE STORMS IMPACTS ON BUILDING
CONSTRUCTION: Loads, Codes and Costs
Comparison of Weather Risks
Catastrophic Losses
Comparison by number per year
Country
(1985: 1st quarter through 1991: 4th quarter)
Thndrstrm
USA
2%
5.4%
3%
32.3%
Wind Related
Damages = 86.6%
10.6%
Public Perception of Hurricanes
43.7%
William M. Gray, Professor Atmospheric Sciences, CSU
Tornadoes Wintr Str Hurrican Flsh Fld
10,000
1,000
10
10
1,000
500
80
0
10
100
500
10
20
0
10
100
8
10
0
10
100
8
10
0
10
500
8
10
10
50
100
10
10
0
10
5,000
10
20
0
100
10,000
8
5
20
500
“ It’s funny. People remember earthquakes a lot
more than they do hurricanes. But in the United
States the number of people who have been killed
this century by hurricanes is 10 times greater.”
E arth q u ake
Relative no.
casualties
H u rr ican e
Hurricane
Fire
Earthquake
Freezing
Windstorm
Tornado
2F1
1
F1
0
2
4
6
8
3
10
1T & F1
Current Potential for Catastrophic
Losses in the United States
Wind Damage Mitigation Challenges
Bob Sheets (former director National Hurricane Center), 1995
PIf Hurricane Andrew had tracked 20 miles further
north “total property damage would have
exceeded $100,000,000,000"
PHurricanes like we had in the 40's and 50's today
would cost:
What is the problem?
$68,000,000,000 in Maryland and Virginia
$106,000,000,000 in south Florida
$104,000,000,000 in New England
4
5T
P Why do economic losses resulting from damage by wind continue
to rise?
P Answer:
 Population density continues to increase along coasts
 Increased use of manufactured housing and mobile homes
 Complex geometry of 1 and 2 story home designs
 Large rapidly constructed housing developments without proper
inspection.
56T
WIND
RESEARCH &
DESIGN
Need for a National
Wind Engineering Initiative
Wind Damage Mitigation Challenges
Current Wind Hazard Research $
Gauss (1997) President,
American Association of Wind Engineering
Reasons for low implementation of wind research
and design information
What hinders improvements?
P Obstacles to damage mitigation include:
 Building code provisions are not complied with
 Building construction is often inferior
 Workmanship in attachment of roof cladding is poor
 Inferior quality materials are used
 Inspection is not comprehensive
 Building permits are issued on the basis of drawings that do not
reveal lateral load paths
7T
6
Wind Damage Mitigation Challenges
P
P
P
P
P
P
Fragmentation of engineering, architectural and design communities
Fear that inclusion of improved designs will increase costs
Framentation of responsible federal and local governments
Poor communication of new information
Indifference
Ignorance
PUS spends < $4 million/year on
wind hazard mitigation
PNSF spends < $750 thousand/year
on wind hazard mitigation
PDuring Hurricane Andrew losses
accrued at $100 million/min for
four hours; hence, entire 1995
federal expenditure was
consumed in 3 seconds
$70 loss
$45 loss
$1000 loss
per $ loss
$1 $1
lossresearch
per $1 research
Earthquakes
Flood hazards
Wind hazards
76T
83T
Wind Engineering Research
For the 2000 s
Smart Buildings
What changes would improve mitigation?
 Critique current boundary layer wind profiles used to simulate
nonstationary extreme wind events
 Develop design and attachment standards for roof coverings
 Determine failure life for facade elements and roof sheathings
 Develop code provisions for resistance tests of facade to
impacts
 Develop CFD sufficiently to permit systematic parameteric
studies of geometrical elements
SMART BUILDINGS
WIND ENGINEERING RESEARCH FOR THE 2000s
Measures Winds
Anticipates Severe Winds
Responds to Mitigate Damage
Smart Buildings
Examples:
Viscoeslastic dampers
Sloshing dampers
Pendlum dampers
Tuned mass dampers
Hydraulic rams
Activated counter-weights
Expert Systems
Computer Friendly Building Codes
Improved Building Systems
Better Post-disaster Reconstruction
9
Expert Systems &
Computer Friendly Codes
Beter Post-disaster Construction
Improved Building Systems
EXPERT SYSTEMS
11
10
IMPROVED BUILDING SYSTEMS
BE TTE R P O S T-D IS AS TE R
RE C O NS TR UC TIO N
Better Wind Load Specification
Better Use of Technology
Share Expert Experience
Interactive Programs
Inferential Reasoning
Inter-disciplinary Research
Co m puter G rap hics
Improved Building Codes
Exp ert System s
Quality Assurance Programs
COMPUTER FRIENDLY
BUILDING CODES
&
Critical Path Techn iques
Redundancy
Co operatio n Betw een R econstruction
and In surance Carriers
Improved Code Enforcement
ANSI-A58.1-1982
ASCE-7
12
13
Prepared by Robert N. Meroney, June 2000
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