Experimental study of steel beam-column joints with novel slot-bolted connections under a central-column-removal scenario

Due to the ample clearance provided by fin plate (FP) and top-and-seat with web angel (TSWA) connections for erection purposes, FP and TSWA connections are commonly utilised in steel structures. In addition, to provide alternate load paths for steel structures under a column-removal scenario, the connections should be sufficiently robust, thereby triggering catenary action. Hence, to improve the robustness of FP and TSWA connections, novel arrangements of slotted holes were proposed for FP and TSWA connections in this study to form novel slot-bolted connections (SBCs). A total of five steel beam-column joint specimens with proposed novel SBCs were tested under a central-column-removal scenario. The experimental results, including failure modes, load–displacement curves, energy absorption capabilities and dynamic resistance, were presented and discussed in detail for all the specimens. The test results revealed that the adoption of proposed novel slotted holes for both FP and TSWA connections could improve their performance in resisting progressive collapse for steel structures. Additionally, to further investigate the behaviour of proposed novel SBCs under extreme loads, the moment–rotation curves of connections were also obtained based on the experimental results. It was found that the presence of slotted holes would decrease the moment capacity of connections, but dramatically increase the rotation capacity. Moreover, the ductility supply of connections with and without the slotted holes was evaluated and compared through the acceptable criteria specified in the design guide for progressive collapse. The comparison showed that the adoption of novel slotted holes could dramatically enhance the plastic rotation capacity for both FP and TSWA connections.