Evaluation of an alternative seismic design approach for rigid wall flexible wood roof diaphragm buildings through probabilistic loss estimation and disaggregation

Abstract

Rigid Wall Flexible roof Diaphragm (RWFD) buildings, commonly referred to as “big-box” buildings are the most prevalent type of construction for low-rise industrial and warehouse facilities in the United States (US). These buildings usually incorporate rigid-in plane concrete tilt-up walls and flexible wood roof diaphragms, which is a commonly seen construction technique in the Western United States. Due to their vulnerability in high seismic areas (e.g. California) observed in past earthquakes, an alternative design methodology was introduced in the FEMA P1026 document to account for the response of the flexible roof diaphragm. The FEMA P1026 design approach has been validated through numerical collapse assessment studies. In this study, the Performance-Based Earthquake Engineering framework, introduced by the Pacific Earthquake Engineering Research (PEER) center, is combined with Monte Carlo Simulation to evaluate, in a probabilistic sense, the earthquake-induced economic losses for these structures. The results are presented in terms of expected losses for two hazard intensities: Maximum Considered Earthquake (MCE) and Design Earthquake (DE), while loss disaggregation plots for collapse and no-collapse losses are also presented. The results demonstrate the ability of the FEMA P1026 design approach to reduce earthquake losses compared to current code-conforming RWFD buildings. Additionally, the results can provide damage and loss information for modeling of these types of buildings within a resilient community and other spatially focused analyses.