钢板笼混凝土短柱抗震性能试验研究

Experimental study on seismic performance of concrete short column with prefabricated cage system

地震作用下的建筑物或构筑物的混凝土短柱易发生脆性破坏,引起结构的严重破坏甚至倒塌;钢板笼混凝土(PCS)是混凝土结构体系的一个重要补充,研究PCS短柱的抗震性能对PCS结构体系的科学研究和工程运用具有重要的参考意义。通过对7个PCS短柱以及1个RC短柱对比件进行低周反复荷载试验,研究板厚、轴压比和横向钢板条间距对试件的破坏形态、滞回性能、骨架曲线、承载力、延性、耗能性能以及刚度与承载力退化的影响,并对其进行累积损伤分析。研究结果表明:试件均发生剪切脆性破坏,PCS试件中横向钢板条易断裂,但相比于RC试件短柱,其耗能能力、承载力及延性均有明显的提高;试件横向钢板条间距减小,有利于发挥PCS短柱的受剪性能,表现出较好的延性和耗能能力;PCS试件的承载力先随板厚的增大而增大,但当板厚增大到界限值后,受剪承载力反而下降;采用基于能量耗散原理和试件在低周反复荷载作用下的P-Δ滞回曲线所建立的累积损伤评价模型,能较真实地反映在低周反复荷载作用下PCS试件的累积损伤状态。

Under seismic loads, the short columns of the buildings and structures are prone to brittle failure, thereby inducing serious damage or even collapse of the structure. The prefabricated cage system(PCS) is an important addition to the reinforced concrete system. The research on the seismic performance of PCS short columns has an important reference for the scientific research and engineering application of the PCS structure system. The low-cycle reversed loading tests were carried out on seven PCS short column specimens and one reinforced concrete(RC) short column specimen for comparison. The influence of steel plate thickness, axial compression ratio and the transverse spacing of steel lathing on failure modes, hysteretic performance, skeleton curves, bearing capacity, ductility, dissipation performance and the degradation of stiffness and ultimate capacity were studied, and the cumulative damage analysis was performed. The research results show that all the specimens are subject to brittle shear failure, and the transverse steel lathing is liable to fracture, but the dissipation capacity, bearing capacity, and ductility of PCS specimens are notably improved compared to those of the RC short column. The reduction of the transverse spacing of steel lathing is favorable for improving the shear resistance of PCS short column, showing better ductility and energy dissipation. The bearing capacity of PCS specimens increase with the increase of plate thickness first, while the plate thickness increases to a certain limit value, the shear bearing capacity decreases instead. The cumulative damage evaluation model established based on the principle of energy dissipation and hysteretic curves of specimens considering P-Δ effect under low-cycle reversed load can reflect the cumulative damage status of PCS specimens with high accuracy.