超高性能混凝土连接装配式柱抗震性能试验研究

为了改善装配式结构中构件连接部位的抗震性能，提出采用超高性能混凝土（UHPC）连接预制柱. 设计1个普通混凝土（NC）整浇柱和6个塑性铰区采用UHPC的装配式柱，通过拟静力试验，研究轴压比、搭接长度、配箍率、搭接段配置短钢筋对试件破坏形态、滞回特性、承载力、变形能力、耗能能力等的影响. 结果表明，搭接长度为8倍钢筋直径的装配式柱的各项抗震性能均高于普通混凝土整浇试件，可以实现与现浇整体柱相同的效果. 随着搭接长度的增大，装配式柱的承载力逐渐增大，变形能力与耗能能力显著提高. 在搭接区段设置短钢筋，可以提高装配式柱的受弯承载力，改变破坏形态，使塑性铰区上移. 基于试验结果，考虑UHPC的受拉作用，提出UHPC装配式柱的正截面受弯承载力计算公式，计算值与试验值吻合较好.

Experimental study on seismic performance of ultra-high performance concrete connected precast columns

Ultra-high performance concrete (UHPC) was proposed to connect precast columns in order to improve the seismic performance of member connections in precast structures. Six precast columns constructed with UHPC in plastic hinge zones and one normal concrete (NC) cast-in-place column were tested under the quasi-static tests. The effects of the axial load ratio, lap length, stirrup ratio and setting of short steel bar on failure modes, hysteretic characteristics, bearing capacity, deformation capacity and energy dissipation capacity of the specimens were analyzed. Results showed that the seismic performance of precast columns with lap length being 8 times the diameter of the steel bar was higher than that of normal concrete cast-in-place columns, which can achieve the same effect as the normal concrete cast-in-place column. The bearing capacity of precast columns gradually increases, and the deformation capacity and energy dissipation capacity significantly increase with the increase of lap length. The setting of short steel bar in the lap-splicing section can improve the flexural bearing capacity of the precast column, change the failure mode and move the plastic hinge area upward. A formula based on the test results for calculating the flexural capacity of precast columns was proposed by considering the tensile strength of UHPC, and the calculated results accorded well with the test results.