水平双向反复荷载作用下RC矩形空心桥墩的滞回模型研究

为了评价复杂地震荷载作用下钢筋混凝土(RC)空心桥墩的抗震性能,对3根RC矩形空心桥墩进行了"回型"水平双向反复荷载作用下的拟静力试验,并基于有限元数值分析方法,研究了该类加载制度下RC矩形空心桥墩的水平力-位移滞回曲线,及双向弯曲作用下RC矩形空心截面的弯矩-曲率。分析探讨了轴压比、壁厚、双轴弯曲强度比参数影响下RC矩形空心桥墩的滞回特性、破坏特征和截面受力性能模拟结果,提出了"回型"水平双向加载下RC矩形空心桥墩的滞回曲线模型,该模型考虑了水平双向加载对构件强度、刚度和位移的耦合效应。应用该模型得到的RC矩形空心桥墩的水平力-位移骨架曲线和滞回曲线的计算值与试验结果吻合较好。

STUDY ON HYSTERETIC MODEL OF RC BRIDGE PIER WITH RECTANGULAR HOLLOW SECTION UNDER LATERAL-BIRECTIONAL CYCLIC LOAD

In order to estimate seismic performance of RC (reinforced concrete) bridge piers with hollow sections under composite earthquake loads, quasi-static testing was carried out on three RC rectangular hollow bridge piers under bidirectional cyclic load with a spiral shape loading protocol. Using finite element numerical analysis, the lateral displacement-force curves and curvature-moment curves of specimens were studied. The parameters considered were axial-compression ratio, wall thickness, and bi-axial bending strength ratio. By analyzing the effect of these parameters on the hysteretic behaviors of specimens, failure characteristics, and section performance, a new lateral displacement-force hysteretic curve model under bidirectional cyclic load with a spiral shape loading protocol was proposed. In the new hysteretic model, the coupling effect on strength, stiffness, and displacement under lateral bidirectional load was referenced. Then the proposed model was further used to obtain calculated lateral displacement-force curves, which agree well with experimental results.