Rethinking Treatment of Irreparability in the Context of Performance-Based Earthquake Engineering

FEMA P-58 is comprehensive performance-based earthquake engineering (PBEE) loss estimation framework which incorporates a three-module Monte Carlo simulation (MCS) procedure to assess the seismic performance of buildings. Although the framework is component-based—it accumulates damage from all building components to estimate the building-level losses, each simulation first checks for two system—or building-level damage states, namely, collapse and irreparability. The current version of FEMA P-58 estimates irreparability solely based on the residual drift of the building, but in reality an impacted building may be condemned for demolition depending on a variety of factors which include structural, strategic, and financial decision variables. In order to overcome the observed shortcomings, a revised loss assessment framework is proposed in this paper. Thereafter, two illustrative examples are presented whereby the vulnerability functions for two select building types are assessed and compared using the proposed new method and the FEMA P-58 approach. The analysis results show that the inclusion of the FEMA P-58 irreparability model often results in overestimation of direct building losses.