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Abstract

Currently enforced building code requirements for earthquakes, including the guidelines for seismic design of tall buildings using non-prescriptive design procedures, are primarily intended to minimize life-safety risks due to structural damage under extreme earthquakes. While tall buildings designed under current standards are expected to achieve such life-safety goal, this study estimates their performance could require recovery times on the order of 3 to 9 months to repair damage from a designlevel earthquake (roughly equivalent to ground motion shaking with a 10% chance of exceedance in 50 years). This study evaluates how recovery-based design guidelines may address these extensive downtime risks by enforcing: (i) tighter drift limits under expected ground motions; (ii) enhanced design criteria for critical nonstructural components; and (iii) measures to mitigate externalities that impede recovery. To illustrate these findings, a 42-story residential reinforced concrete shear wall building in San Francisco, CA is used as a case study. This paper is a summary of Part 3 of San Francisco’s Tall Buildings Study, a recently completed Applied Technology Council Project for the City and County of San Francisco, in which the authors participated.