Seismic Performance of Buildings with Special Steel Moment Frames Using Modified End Plate and Shear Plate Connections

Abstract

Nonlinear response history analyses were conducted to determine the seismic collapse safety and seismic performance of buildings with special steel moment frames using Simpson Strong-Tie Strong-Frame moment frames compared to equivalent buildings using reduced beam section (RBS) moment frames. The Strong-Frame moment connection consists of a modified T-stub or end plate connection incorporating Yield-Link structural fuses for moment transfer, and a modified shear plate connection for shear transfer. Archetypical 4-story, 8-story, 12-story, and 20-story steel frame buildings designed using ASCE 7-16 were evaluated. The results indicate that the Strong-Frame buildings have a 36% larger adjusted collapse margin ratio and are less likely to collapse, compared to the RBS buildings. The Strong-Frame buildings also have lower probable repair costs and shorter repair time compared to the RBS buildings. The improved collapse safety and enhanced performance of the Strong-Frame buildings are attributed to the stronger column web panel zone, inclusion of column bending moments in seismic overstrength load combinations, delayed connection strength degradation, a distributed global collapse mechanism, and replaceable connection components.