Method for probabilistic evaluation of post-earthquake functionality of building systems

Recent large earthquakes have caused significant building damage resulting in lengthy functional recovery times. Post-earthquake recovery time can be minimized through improved design of building systems essential for providing continuous operation. This study presents a novel method for probabilistic evaluation of the post-earthquake building's functionality to support functionality-based seismic design. Aligned with the PBEE methodology, the proposed method utilizes FEMA P-58 damage assessment results in conjunction with fault trees of complex building systems to find the percent of building area with compromised functionality and to identify building components that impair its functionality. The primary user-defined inputs are probabilistic limit state functions of individual building components, which define the damage thresholds for partial (local) and full loss of the building functionality. The proposed method is highly flexible; it has a modular structure that allows easy extension by adding new features. A case study is conducted for an existing 13-story building to demonstrate the functionality evaluation and showcase how its results can guide the retrofit measures for improved seismic performance.