Seismic Fragility Assessment of SMRFs with Drilled Flange Connections using Ground Motion Variability

Abstract

Seismic behavior of Steel Moment Resisting Frames (SMRFs) with Drilled Flange (DF) connections as well as Reduced Beam Section (RBS) and Welded Unreinforced Flange-Bolted web (WUF-B) as a Pre-Northridge connection have been compared analytically considering Far-field earthquake-induced. The backbone curves of RBS and WUF connections are extracted from available studies and the backbone curve of DF connection is presented in this study in order to simulating the buildings models. DF, RBS, WUF connections and Panel Zone (PZ) are numerically modeled based on the proposed models provided by the prior researches and these models are applied to analyze low- and high-rise buildings designed in accordance with the relevant standards. Incremental Dynamic Analysis (IDA) process is utilized to evaluate the effects of DF connection on structural seismic response of SMRFs. Afterwards, the structures’ performance in different response levels is probabilistically assessed by means of IDA and fragility curves. The results show that the seismic demand of SMRFs with DF and RBS connections are so similar, specifically for low-rise buildings. Likewise, SMRFs with DF connection provide up to 43% higher seismic demand in high-rise buildings compared to RBS connection. Eventually, DF connection can be used as an authentic option in SMRFs.