Numerically Based Seismic Fragility Curves for Suspended Ceiling Systems

This paper presents numerically generated seismic fragility curves for several configurations of suspended ceiling systems. The main objective is to showcase a numerically driven approach to constructing seismic fragility curves for suspended ceiling systems compared to the FEMA P-58 methodology, where the seismic fragility curves were developed based on a limited number of expensive large-scale shake table experiments. Four finite element (FE) archetype models of suspended ceiling systems were developed adhering to the seismic design guidelines provided by ASTM E580/E580M standard for Seismic Design Categories D and E in the United States with plan areas ranging from 13.4 m2 (144 ft2) to 251.2 m2 (2704 ft2). The recorded floor motions from available sample steel buildings subjected to FEMA P695 far-field ground motions were used as input loading to these FE models of suspended ceiling systems. Based on the predictions of nonlinear dynamic analysis of these FE models, key parameters, such as median peak floor acceleration (PFA) and log-normal standard deviation, of seismic fragility curves were estimated. Notably, the FE models consistently predicted greater median PFA values than that of the prescribed values by the FEMA P-58 methodology. In addition, similar studies were conducted on the FE model of a suspended ceiling system designed for Seismic Design Category C with a plan area of 13.4 m2 (144 ft2). For this case, the FE model predicted smaller median PFA values than that of the prescribed values by the FEMA P-58 methodology. These differences can be attributed to the fact that the median PFA values prescribed by the FEMA P-58 methodology were interpolated from limited experimental data. Therefore, the findings of this study provide a complementary and much-needed robust data set when reliable experimental information is scarce or unavailable for generating seismic fragility curves for suspended ceiling systems.