EXPERIMENTAL STUDY ON THE SEISMIC PERFORMANCE OF JOINTS BETWEEN SIDEWALLS AND FLOORS IN PARTIALLY PREFABRICATED SUBWAY STATION

A novel joint between the sidewall and the station floor was proposed for partially prefabricated subway stations. The internal force transmission between the partially precast sidewall and corresponding subway station floor was achieved through overlapping U-bars extending from them respectively. To investigate the seismic performance of the assembly joint, three full-scale precast joint specimens with different positions of the lap connection and one full-scale cast-in-place concrete joint specimen for comparison were designed and produced based on an actual engineering project. Quasi-static tests and finite element analysis were conducted on these four full-scale joint specimens. The critical seismic performance associated with the joints, including the failure pattern, bearing capacity, hysteretic characteristics, and mechanical performance of U-bars overlapping connection were analyzed. The results show that the local concrete compression failure inside the hook of the U-bars and the brittle fracture of the loop are the two main failure modes in the lap connection of assembly joints. Both failure modules can be attributed to the degradation of the bond between reinforcement and concrete. When the U-bars are overlapped in the haunched segment, the bearing capacity, failure pattern, and hysteretic characteristics of assembly joints are similar to those of the cast-in-place concrete joints. If failure of reinforcing steel bars bonding can be prevented, the U-bars overlapped outside the haunched segment can effectively increase the shear resistance of the joints.