ASCE 41-13: Seismic Evaluation and Retrofit Rehabilitation of Existing Buildings

TLDR

The standard allows users to choose between lower performance objectives for existing buildings, similar to the Basic Safety Objective in ASCE 41, or hazard levels comparable to new buildings. Over the past three years, the ASCE/SEI Standards Committee on Seismic Rehabilitation has merged ASCE 31‑03 into ASCE 41‑06 and updated both standards. The forthcoming ASCE 41‑13 eliminates prior inconsistencies, reorganizes Tier 1 checklists, expands Tier 2 deficiency‑only procedures, and incorporates numerous technical updates such as nonlinear response‑history analysis, bucking‑restrained‑braced‑frame provisions, liquefaction, foundation rocking, URM, and seismic isolation chapters.

Abstract

For the past 3 years the ASCE/SEI Standards Committee on Seismic Rehabilitation has been working to combine ASCE 31-03 into ASCE 41-06 while also updating both standards. The result of that humongous effort is the soon-to-be released ASCE 41-13: Seismic Evaluation and Retrofit of Existing Buildings. The new combined standard has eliminated any inconsistencies that previously existed between the two standards. Now the user decides if they want to go forward with lower performance objectives traditionally used for existing buildings, as was the case within ASCE 31 or an equivalent hazard to a new building, similar to the Basic Safety Objective in ASCE 41. In addition, the Tier 1 checklists have been significantly modified and reorganized. The use deficiency-only procedures (Tier 2) have been greatly expanded to regular buildings of greater heights. Plus, there have been a number of significant technical changes including updated analysis provisions with more emphasis on nonlinear response history analysis, provisions for bucking restrained braced frames, expanded liquefaction provisions, a new foundation rocking analysis procedure, substantially updated URM provisions, and a full updated Chapter on Seismic isolation and Energy dissipation.