Impact of gravity frames on collapse performance of special steel moment frames

Abstract

Probabilistic collapse analysis procedure, P-695, which is a methodology used for the determination of seismic design parameters such as response modification factors and deflection amplification factors along with seismic performance evaluation of structural systems, does not consider the contribution of gravity-load-carrying system to the lateral stiffness and strength. Considering the fact that shear connections are capable of transferring 25% and 40% of the beam's stiffness and strength, respectively, ignoring the impact of this extra capacity on the non-linear behavior might lead to inaccurate seismic evaluation of structures. This study aims to investigate the impact of gravity frames on the seismic performance of steel structures through numerical methods. For this purpose, incremental dynamic analyses are carried on two different frames and the results are compared using probabilistic collapse analysis methodology, P-695. The assessment conducted herein pointed out that the gravity frame played a critical role in the collapse performance of the selected mid-rise structure.