Experimental study on seismic performance of damaged steel concrete special-shaped beam-column joints reinforced by manually compacted ultra-high performance concrete

In order to study the seismic performance of the damaged steel concrete special-shaped beam-column joints reinforced by manually compacted ultra-high performance concrete (UHPC), cyclic hysteresis loading tests were carried on two profiled concrete beam-column joint specimens before and after the reinforcement. The failure mode, load carrying capacity, deformation, hysteresis curves, skeleton curves, strength degradation, stiffness degradation, and energy dissipation capacity of the specimens were compared before and after reinforcement. The results show that the bonding performance between UHPC material and ordinary concrete was very good. After UHPC reinforcement, the bearing capacity of the damaged joints can be basically restored to the intact state, and the energy-consuming capacity increased, but the stiffness degradation was obvious. It is recommended that when using UHPC for joint reinforcement, the effect of forming ring wrap in the joint area is better. The research conclusion can provide reference for the design and popularization of UHPC and has certain theoretical and practical value.