Effects of near-field earthquakes, connection types, and SSI on seismic performance of SMRF

This study aims to validate the ASCE7-16 code, which investigates the effects of near-field earthquakes, SoilStructure Interaction (SSI), and connection types on the seismic performance of the code-conforming Steel Special Moment-Resisting Frames (SMRFs). To this end, three structures with 4, 9, and 16 stories representing low, mid, and high-rise buildings are designed, respectively, according to the ASCE7-16 and AISC 360-16 codes. In order to evaluate the effect of connections' type on the seismic performance, two prequalified connections, namely Welded Unreinforced Flange-welded Web (WUF-W) and Reduced Beam Section (RBS) are taken into account. Afterward, for the sake of seismic assessment, an internal frame is selected from each building model, in which, the Nonlinear Time-History Analysis (NTHA) is conducted using OpenSees software. Then, a set of farfield and three sets of near-field (with/without pulse-like records, including forward-directivity as well as fling-step) ground motions are selected, where each set consist of 12 earthquake records. The Inter-story Drift Ratio (IDR) is considered as a major indicator to assess the seismic performance of the structures. Based on the obtained results, subject to the pulse-like ground motion records, the IDR values exceed the allowable limits specified by ASCE 7-16, and additionally, it is found that the SSI effects change the height-wise distribution of the IDR, highlighting the need for revising the provisions of ASCE 7-16. Eventually, the seismic responses are investigated according to ASCE 41-17 and the performance limits of the structures are obtained accordingly. The results indicate that all structures manage to satisfy the acceptable performance limits.