Seismic Fragility Analysis of Buildings Equipped with Propped Rocking Wall Systems

This paper presents a seismic vulnerability assessment study on a newly proposed seismic force resisting system named Propped Rocking Walls (PRW) based on the Methodology presented in FEMA P695. Propped rocking wall is a form of seismic-force resisting system that combines unbonded post-tensioned (PT) concrete walls with passive supplemental damping devices. This study is aimed at verifying the adequacy of a proposed direct displacement-based design procedure for propped rocking walls through evaluating global/local failure capacity of the proposed system. To this end, seismic fragility curves for predefined performance limit states were developed for a PRW prototype system through cumulative distribution functions under the FEMA P695 Far-Field ground motions set. The seismic response of the PRW numerical model used for this evaluation was validated with shake table test results conducted previous to this study. Results from this evaluation confirmed that the specific PRW prototype system considered in this study meets the FEMA P695 criteria regarding the margin of safety against collapse probabilities under MCE ground motions.