Session IVa – "A Seismic Rehabilitation Agenda for Older Hazardous Concrete Buildings"
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Session IVa – "A Seismic Session IVa – "A Seismic Rehabilitation Agenda for Rehabilitation Agenda for Older Hazardous Concrete Older Hazardous Concrete Buildings" Buildings" Richard McCarthy Richard McCarthy Executive Director Executive Director California Seismic Safety Commission California Seismic Safety Commission
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Session IVa – "A Seismic Rehabilitation Agenda for Older Hazardous Concrete Buildings". Richard McCarthy Executive Director California Seismic Safety Commission. Mitigation of Seismic Risk in Older Concrete Buildings. EERI Concrete Building Coalition and NEESR Grand Challenge - PowerPoint PPT Presentation
Transcript of Session IVa – "A Seismic Rehabilitation Agenda for Older Hazardous Concrete Buildings"
Session IVa – "A Seismic Session IVa – "A Seismic Rehabilitation Agenda for Older Rehabilitation Agenda for Older Hazardous Concrete Buildings"Hazardous Concrete Buildings"
Richard McCarthyRichard McCarthyExecutive DirectorExecutive Director
California Seismic Safety CommissionCalifornia Seismic Safety Commission
Mitigation of Seismic Risk in Mitigation of Seismic Risk in Older Concrete Buildings Older Concrete Buildings
EERI Concrete Building Coalition EERI Concrete Building Coalition and NEESR Grand Challengeand NEESR Grand Challenge
Craig Comartin and Jack MoehleCraig Comartin and Jack Moehle
Project backgroundProject background
California, 1994 Turkey, 2003
“50% of the casualties are coming from 5% of the buildings.”Kircher et al., “Estimated Losses due to a Repeat of the 1906 San Francisco Earthquake, Earthquake Spectra, 2006.
Project backgroundProject background
OperationalHeavy
Collapse
Mexico City, 1985
Erzincan, 1992
0
20
40
60
80
100
Percentage
Kobe, 1995
Luzon, 1990
Older Concrete Building Damage Rating
Otani (1999)
Otani, 1999
“Current guidelines identify most older concrete buildings as collapse risks.”Craig Comartin, EERI President, 2006 Earthquake Conference
Project thesisProject thesis• Available guidelines are too conservative
– most buildings are found inadequate – retrofit costs are high
• This “always bad” message– is not credible– is impeding action
• Improved procedures– can reduce the problem– can make retrofit programs feasible
• What we learn can be translated to other building types and localities.
Project aimsProject aims
• Develop a consensus on the “killer” buildings
• Demonstrate cost-effective retrofit
• Identify mitigation policy alternatives
• Promote active mitigation programs
Moehle Comerio Ramirez
Mosalam
Project TeamProject Team
Anagnos
Hutchinson
Leadershipteam
Disciplines: Seismic hazard Inventory Simulation Laboratory Field Building Regional Public policy EOT
Stewart
May Matamoros
Steele Lopez
Research program overviewResearch program overview• Inventory
– by structural type
– by occupancy
– by ownership
• Participants– building and safety
– housing agencies
– structural engineers
– real estate professionals
Research program overviewResearch program overview
• Testing to collapse– Multi-directional loadings– Realistic axial loads
• Simple retrofit methods
Research program overviewResearch program overview
• Systems studies – SFSI– Membrane effects
Flexible/Weak Foundation
Research program overviewResearch program overview
• Improved simulation– model development– simulation capability
• Regional simulation0
50
100
150
200
250
300
350
400
450
0 2 4 6 8
Displacement
Shear
Monotonic
CyclicEnvelope
FEMA 356
Research program overviewResearch program overview
• Crafting and evaluating appropriate policies– Identify different classes of the problem
• Structural configuration• Occupancy• Economic conditions
– Identify feasible mechanisms– Model risk reduction impacts– Evaluate economic impacts
• Costs borne by building owners, governments, and other stakeholders
• Regulatory considerations
Collaborations with existing Collaborations with existing organizationsorganizations
• ASCE Standards Committees
• American Concrete Institute
• Applied Technology Council
• EERI Concrete Coalition
