Performance of Various Steel Moment Connections Under Progressive Collapse Scenario

Abstract:

Based on computational modelling and energy flow perspective, this paper investigates the failure process and dynamic responses of three types of connections, including web unreinforced flange bolted (WUFB), web cover plated flange (WCPF) and reduced beam section (RBS) under progressive collapse scenario. The results show that the WCPF connection has strong rotational and tensile capacities, and the corresponding beamcolumn assembly has stout flexure mechanism and catenary action. It follows that the beamcolumn assembly with the WCPF connection has high energy absorption capacity and favorable performance under disproportional collapse scenario. The RBS connection has strong rotational capacity, and the corresponding beamcolumn assembly has strong catenary action mechanism and improved energy absorption capacity. However, the RBS connection has reduced flexural stiffness, and thus the external work done by the same gravity load of the corresponding beamcolumn assembly is maximum, which contributes to the slightly lower bearing capacity of the RBS connection under progressive collapse scenario. The study also indicates that the stress states of connections under progressive collapse scenario are quite different from those in seismic tests and that the rotational capacities of connections under progressive collapse scenario are significantly greater than those in earthquakes.