Seismic evaluation of composite moment frames subjected to near-fault ground motions

Abstract

This paper investigates the seismic behavior of composite special moment frames (CSMF) under near-fault ground motions. For this purpose, two factors, response modification and deflection amplification are chosen. 3-, 9- and 20-story frames of SAC joint venture are modeled in OpenSees software. The nonlinear behavior of the panel zone was modeled using a 2D joint element and a tri-linear relation. FEMA p695 near-fault ground motions are applied in Incremental Dynamic Analysis (IDA). Ultimately, the obtained results are compared to the values recommended by ASCE provisions. The average results indicate that the ASCE provision can appropriately predict the response modification factor; however, in the case of deflection amplitude, IDA results may not show good agreement with ASCE/SEI 7 suggested value. Also, by comparing the results of composite special moment frames with steel moment frames from literature, it has been revealed that, unlike ductility, overstrength increases significantly when concrete filled tube columns are employed in special moment frames.