Seismic performance of superposed shear wall- superposed floor slab joints

Superposed shear walls are widely used in high-rise buildings, in which shear wall-floor slab joints play an important role in the structural seismic resistance. To investigate the seismic performance of superposed shear wall-superposed floor slab joints(SWS)under vertical seismic forces, two full-scale joint specimens were fabricated and subjected to low-cyclic reciprocal load to analyze their failure modes, hysteresis properties, ductility, stiffness degradation, and energy dissipation capacity. In comparison to the cast-in-place specimen, when the precast side of the floor slab is in compression, the overall damage of the SWS specimen is sound, with indexes of seismic performance being close; when the precast side of the floor slab is in tension, due to the bending up of the longitudinal tensile reinforcement, the effective bearing area decreases, resulting in the reduction of the load-bearing capacity and energy dissipation performance. By comparing the results of ABAQUS finite element (FE) simulation analysis with the experimental results, the equivalent plastic strain nephogram of concrete and the Mises cloud diagram of reinforcement are confirmed to be consistent with the experimental results, and the trends of the hysteresis loop and skeleton curves are also in reasonably good agreement. On this basis, the influence of distinct connection methods at the joints on the structural seismic performance was examined by means of FE simulations. The findings demonstrate that the seismic performance of the SWS specimen is effectively enhanced by the direct extension of longitudinal tensile reinforcement in the precast layer of the floor slab connected to the shear wall.