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Updating ASCE 31 and 41 A Report from the ASCE Standards Committee on Seismic Rehabilitation Chris Poland, S.E. – Chair Robert Pekelnicky, S.E. – Vice-Chair Degenkolb Engineers ASCE Standards for Seismic Rehabilitation ASCE 31 Seismic Evaluation of Existing Buildings Deficiency based
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Updating ASCE 31 and 41A Report from the ASCE Standards Committee on Seismic Rehabilitation Chris Poland, S.E. – Chair Robert Pekelnicky, S.E. – Vice-Chair Degenkolb Engineers
ASCE Standards for Seismic Rehabilitation ASCE 31 Seismic Evaluation of Existing Buildings Deficiency based Three tiered evaluation procedure Performance based Focuses on validating buildings 2003 ASCE 41 Seismic Rehabilitation of Existing Buildings Tool kit of procedures and acceptance criteria Force based and displacement based analysis Systematic and Simplified procedures Performance based 2008
ASCE 31/41 Update • Committee reconvened on December 9 and will operate under new format similar to ASCE 7. • Updates to ASCE 31 and 41 in 3 years • Combine and/or streamline ASCE 31 and 41 for a seamless transition.
ASCE 31 Issues • Step function between ASCE 31 and 41 • Does not use same seismic hazard as 41 • Nonstructural Checklists too extensive • Tier 1 Life Safety Checklists could be simplified • Does not address resiliency and down time, but could with some additions
ASCE 41 Issues • Does not currently use RTE hazards • Global damage parameters needed • SSI procedures need refinement • Many acceptance criteria overly conservative • LSP is overly conservative • Solicit and accept modifications from materials standards organizations • Case studies needed • Transition from guideline to standard may have resulted in unnecessary requirements
Policies for Achieving Resilience • Advocate for a Resilient City through transparent hazard declaration. • Refine and declare the hazard level and performance categories used in design. • Predict performance accurately • Tailor performance to response needs • Residential structure must allow occupants to shelter in place • Keep the big picture in mind • Speak with a common voice • Refer to 2/09 Urbanist at www.spur.org