基于UHPC壳的装配式混凝土梁柱连接抗震性能研究

Study on seismic performance of precast concrete beam-column connections with UHPC shells

为提高装配式混凝土框架梁柱连接的抗震性能、减小施工难度、便于震后修复,提出一种基于UHPC壳的装配式混凝土梁柱连接。为研究该连接的抗震性能和预制UHPC壳长度带来的影响,开展2个足尺预制试件的低周反复荷载试验,与现浇对比试件进行对比,详细考察试件破坏模式,分析滞回曲线、骨架曲线、强度和延性、强度退化和刚度退化规律、耗能能力、塑性铰长度等。研究表明,基于UHPC壳的装配式混凝土梁柱连接试件抗震性能良好;预制UHPC壳的设置,减缓了梁端下部混凝土的损伤,有利于震后修复,梁端上部叠合层混凝土破坏程度相对于现浇试件略为严重;较长的预制UHPC壳更加有利于降低预制试件的混凝土损伤,提高试件的极限变形能力和延性。论文为该类新型节点抗震性能研究提供了宝贵的试验数据。

To improve seismic performance of beam-column connections in a precast concrete frame, reduce the construction difficulties and help to rehabilitate the damaged structures after earthquakes, a novel precast concrete beam-column connection with UHPC shells was proposed.To investigate the seismic performance of this connection and the influence of the length of the U-shaped shells, two full-scaled precast specimens were tested under low-cycle reciprocating loadings.The results were compared with those of the monolithic reference specimens, and furthermore the hysteresis curves, skeleton curves, strength and ductility, deterioration of strength and stiffness, energy dissipation capacities and plastic hinge length were analyzed.The results indicate that the seismic performance of precast concrete beam-column connections locally reinforced by prefabricated UHPC elements is satisfactory;the damage of the concrete at the beam bottom is reduced by setting prefabricated UHPC shells, which is beneficial to rehabilitation of the damaged structures after earthquakes, and the damage to the monolithic layer at the beam top becomes more severe;the longer prefabricated UHPC shells can help reduce the damage to the precast concrete elements and improve the ultimate deformability and ductility.This work provides valuable experimental data for the seismic performance research of this new type of joint.