Research on the seismic performance of novel side-plate reinforced beam-column composite joints

To determine the failure modes and seismic behavior of composite joint specimens with a flush beam-flange sideplate (FBSP) connection, a bare steel beam joint specimen and two composite joint specimens with different composite steel-concrete slabs were tested under cyclic loading. The joints were classified and comprehensively evaluated. Furthermore, finite element analysis was conducted on the connection details and the slab width. It can be concluded that the bare steel beam joint specimen experienced plastic hinge failure. The failure phenomenon of the composite joint specimens manifested as fracture failure of the fillet weld between the bottom beam flanges and cover plates. According to Eurocode 3, all the joint specimens were classified as full-strength joints. The bare steel beam joint was rigid in non-sway frames, while the composite joint was semirigid when classified by stiffness. Comparing the results of the composite joint specimens, the comprehensive performance of the specimen with the steel-bar truss deck concrete slab was relatively balanced. There was no significant change in the flexural capacity whether the top beam flange was directly connected to the column wall or adopted a bolted bottom beam flange, but the ductility significantly increased. The flexural capacity and fracture displacement increased when the bottom cover plates were extended under a sagging moment.