6 - Seismic fragility analysis of steel building portfolios based on mathematical models

Abstract

Chapter 6 aims to provide a thorough procedure on how to accurately create seismic fragility curves for steel building portfolios using mathematical models. The building portfolios are restricted to l-shaped steel moment frame structures (SMFSs) located in the Central-Eastern United States (CEUS). Given the numerous l-shaped SMFSs in the CEUS, their seismic fragility needs to be assessed efficiently. Seismic fragility curves of the l-shaped SMFSs for immediate occupancy (IO), life safety (LS), and collapse prevention (CP) were created using two mathematical models, logistic and Gompertz models. Then, these curves were compared to those from Monte Carlo Simulation (MCS) coupled with lognormal distribution functions, which is the most commonly used fragility model using the results of Chi-squared tests (χ2). It turned out that the mathematical models attained low values of the χ2 signifying high accuracy, and particularly, the Gompertz model was the most accurate model for LS and CP fragility.