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为研究低周反复荷载作用下方钢管再生混凝土柱的恢复力模型,以再生粗骨料取代率和轴压比为变化参数,设计并制作了6个试件,进行拟静力试验。观察试件的破坏形态,实测试件的滞回曲线,综合采用定点指向、位移幅值承载力突降、模型软化点等特殊处理方法,建立以相对屈服点、相对峰值点和相对破坏点为特征点并结合滞回曲线和卸载刚度的三折线荷载—位移恢复力模型。结果表明:试件破坏形态与普通钢管混凝土柱相似,方钢管底部鼓曲破坏,再生混凝土底部被压碎。试件的滞回曲线比较饱满,且稳定性良好。建立的低周反复荷载作用下方钢管再生混凝土构件的三折线恢复力模型与实测滞回曲线吻合较好,建议用于该类新型组合结构的弹塑性地震反应分析。
In order to study the restoring force model of SRC columns under the action of low cycle repeated loading, six test pieces were designed and fabricated with pseudo-static test by taking the replacement ratio of coarse aggregate and axial compression ratio as changing parameters. The destruction morphology of specimens was observed, and the hysteresis curves of the specimens were measured. Special treatment methods such as fixed point pointing, sudden drop of displacement amplitude, softening point of model and so on were established. The relative yield point, relative peak point and relative failure point Trichotomy load - displacement restoring force model combining feature point, hysteresis curve and unloading stiffness. The results show that the failure mode of specimens is similar to that of ordinary CFST columns. The bottom of square steel tube is destroyed by drum damage and the bottom of recycled concrete is crushed. Specimen hysteresis curve is full, and the stability is good. The established tri-fold line restoring force model of the concrete-filled steel tube under low cyclic loading is in good agreement with the measured hysteresis curve, which is suggested for elasto-plastic seismic response analysis of such new composite structures.