轴压下钢筋混凝土桥墩塑性铰特性研究

发布时间：2018-10-11 07:00

【摘要】：通过2个大尺寸钢筋混凝土桥墩在轴压下的水平低周往复加载试验,并结合混凝土压应变方法和基于OpenSEES的数值方法,研究钢筋混凝土桥墩的塑性铰特性,分析轴压对塑性区域长度及等效塑性铰长度的影响规律。结果表明:随轴压的增大,桥墩截面受压区应变增大,桥墩发生塑性破坏区域的长度显著增加,既有规范按1.0倍的桥墩截面高度估计塑性区域长度在高轴压下偏于不安全,故建议当桥墩轴压比超过0.2时,加密布筋的塑性区域长度应增大至1.5倍的桥墩截面高度;随着轴压增大,桥墩位移延性的下降大于截面曲率延性下降的幅度,从而使等效塑性铰长度不断减小,因此在推导等效塑性铰长度时应考虑轴压的影响,以免在轴压较大时过高估计桥墩延性,带来安全隐患。
[Abstract]:In this paper, the plastic hinge characteristics of reinforced concrete pier are studied by the horizontal low-cycle cyclic loading test of two large-sized reinforced concrete piers under axial compression, combined with the concrete compressive strain method and the numerical method based on OpenSEES. The influence of axial compression on the length of plastic region and equivalent plastic hinge is analyzed. The results show that with the increase of axial compression, the strain in the section of piers increases, and the length of the region where plastic failure occurs on the piers increases significantly. The existing codes estimate the length of the plastic region at 1.0 times of the height of the piers under high axial compression, and it is not safe to estimate the length of the plastic region under high axial compression. Therefore, it is suggested that when the axial compression ratio of the pier exceeds 0.2, the plastic region length of the infilled reinforcement should be increased to 1.5 times the height of the pier section, and with the increase of axial pressure, the displacement ductility of the pier decreases more than that of the curvature ductility of the section. Therefore, the influence of axial compression should be taken into account in deriving the length of equivalent plastic hinge, so as to avoid overestimating the ductility of bridge pier when the axial pressure is high, and bring about the hidden danger of safety.
【作者单位】：北京交通大学土木建筑工程学院;吉林大学交通学院;
【基金】：铁道部科技研究开发计划项目(2008G010-A) 优秀博士生创新基金项目(2012YJ074)
【分类号】：U443.22

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