Cyclic Behavior of Slab–Wall Connections with Concrete-Filled Steel Tubes Embedded in Wall Piers

Abstract

Concrete-filled steel tubes (CFSTs) embedded in structural walls can improve the lateral-force resistance of slab–wall structures, but also impede the passage and anchorage of steel bars in slabs around the tubes. Therefore, the objective of this research is to propose the design of anchorage detailing to solve this problem, and analyze the bearing capacity and seismic performance of the joint using this design. Two types of no-through-tube anchorage detailing were put forward for steel bars in slabs that intersect with CFST-strengthened structural walls: (1) an anchoring ring (AR) detailing; (2) a direct anchoring (DA) detailing. Four slab–wall concrete specimens using these two detailing types were tested cyclically. It was found that the connection specimens with the AR detailing had better ductility and energy dissipation capacity compared to those with the DA detailing. Nevertheless, the connection specimens with the DA detailing had more direct force-transferring capacities, meaning that they were better at transferring the force received by the slabs to the shear walls. Overall, both types of detailing can be adopted in practice to significantly improve the seismic performance of slab–wall connections, and the choice of which to use would depend on the specific requirements of a project.