Experimental and numerical research on seismic behavior and shear capacity of SRC column-RC beam composite joints

The seismic behavior of SRC column-RC beam composite joints was investigated experimentally and numerically. Based on the analysis of experimental results, it was considered that the joints were subjected to flexural failure and shear failure in the connection zone, and the stirrup ratio in the connection zone would affect the failure mode. The ductility and energy dissipation capacity of the joints were between the ordinary RC joints and SRC joints. The structural measures of setting ring beams in the connection zone were put forward to improve the characteristics of bearing capacity and ductility asymmetry. The change of concrete grade has little effect on the joint strength, but the increase of the axial compression ratio would significantly reduce the bearing capacity of the joints. When the axial compression ratio was greater than 0.5, it was speculated that the joints would be damaged in other forms. According to the analysis of the shear proportion borne by various components, it was considered that the shear bearing capacity of composite joints was mainly borne by stirrups, steel webs and concrete in the connection zone. Based on the strength superposition method, the shear bearing capacity calculation formula of the joints was established by considering the adverse effect of the axial compression ratio and ignoring the shear contribution of flexural failure concrete.