Investigation on in-plane mechanical behavior of joint connections for discrete connected new-type precast concrete diaphragms

This paper proposes three new types of connectors adopted in discrete connected new-type precast concrete diaphragms (DCNPD). An experimental investigation of innovated connectors under shear load was conducted to evaluate the failure mode, strain and bearing capacity of joint connections in DCNPD. Based on the experimental results, the hairpin connector (HPC) was selected for simulation verification and further analysis under combined loads to provide crucial information on bearing capacity, ductility, reduction rule, deformation and stiffness in order to reveal its working mechanism. The results indicate that three types of connectors can provide effective connection for slab joints. The ideal fracture failure mode of anchor bar or cover plate is realised in all joint connections. The shear capacity of HPC is weakened by simultaneous tension when it is under combined loads. With the increase of tension-to-shear force ratio, the ductility of HPC is improved, and the shear ductility is relatively better. The evaluation of yield displacement and bearing capacity, degradation law in strength, deformation and stiffness of HPC provides a theoretical basis for the development of joint connection and seismic design of DCNPD, which is vital for the application of DCNPD in precast concrete structures.