Seismic performance of precast concrete sandwich walls with bolt-steel plate connection

The bolt-steel plate connection stands as a dry connection method in precast structures characterized by its simplicity, high efficiency, ease of assembly and disassembly, and environmental protection. Five precast concrete sandwich walls (PCSWs) with glass fiber-reinforced polymer (GFRP) to connect the interior and exterior concrete wythes were designed and tested to investigate the seismic performance of such walls under cyclic loads. Ultra-high performance concrete (UHPC) was used to strengthen the bolt-steel plate connection joint. This study investigated the effect of the sandwich wall between the two bolt-steel plate connection joints, opening, and UHPC on the seismic performance of PCSWs. The findings revealed that the sandwich wall between the two bolt-steel plate connection joints, UHPC, and the interface between UHPC and ordinary concrete had a significant influence on the failure modes, including four failure modes: shear failure of bolt-steel plate connection joint, concrete crushing at the wall toe and through-crack of the shear oblique cracks and horizontal joint, shear failure at the interface between the solid and sandwich walls, and shear failure typified by a "Keyway" configuration. The use of UHPC to strengthen the bolt-steel plate connection area could significantly improve the load-bearing capacity and peak drift ratio. Whether the sandwich wall was used in the non-bolt-steel plate connection area in the horizontal joint zone had minimal influence on both the load-bearing capacity and peak drift ratio. For the walls without UHPC strengthening, the ultimate load and ultimate drift ratio could be increased by using the sandwich wall between the two bolt-steel plate connection areas, however, it was the opposite when UHPC strengthening was used. The paper also compared the sandwich walls with the solid walls, and the results showed that the sandwich wall with bolt-steel plate connections had good seismic performance.