Experimental study on the structural behavior of exterior precast concrete beam-column joints with high-strength steel bars in field-cast RPC

Abstract

To enhance the seismic performance of conventional precast concrete frame structures, this study introduces a novel precast high-performance concrete frame beam-column joint. We designed and conducted experiments on two full-scale precast concrete frame beam-column exterior joints, varying the presence of L-shaped steel reinforcement at the bottom of the beam-column joint. The findings reveal that the load-bearing capacity, hysteresis characteristics, stiffness degradation, and energy dissipation capacity of both joints significantly improve when using reactive powder concrete (RPC) poured into the joint connection area and L-shaped steel at the beam-column junction. A finite element model for these joints was further developed and validated based on the experimental data. Additionally, a parametric study was conducted to assess the impact of axial compression ratio and spacing of hoop bars in the joint area on joint behavior. Using an experimental fitting approach, a tri-linear skeleton curve model for the joints was established, offering a more precise representation of stress and deformation characteristics at each stage. The hysteretic curve generated from this restoring force model closely matches the experimental data, demonstrating the model’s ability to accurately depict the hysteretic behavior of beam-column joints in precast RPC/RC composite frames.