内填部分混凝土箱形截面钢桥墩的延性影响参数

摘要

To investigate the ductility behavior of partially concrete⁃filled steel box⁃section bridge piers subjected to a constant vertical load as well as cyclic lateral loads, a three⁃dimensional elastic⁃plastic finite element formulation is proposed for numerical simulation. By comparing the lateral load⁃lateral displacement hysteretic curves and failure modes of numerical results with experimental results, the proposed finite element analysis method is verified to be accurate and effective. 56 analytical models are established with four variable parameters, i.e., flange plate width⁃thickness ratio, column′s slenderness ratio, filled⁃in concrete ratio and axial load ratio. A summary of possible failure modes is given as follows. For pure steel piers, local buckling occurs near the bottom of the specimen. For partially concrete⁃filled steel piers, local buckling usually occurs at the upper plate adjacent to filled⁃in concrete in the case of small filled⁃in concrete ratio. With the increase of filled⁃in concrete ratio, local buckling will appear near the bottom of the specimen. Finally, the ultimate strength and ductility behavior of partially concrete⁃filled steel bridge piers are investigated on the basis of four variable parameters mentioned above.%为了研究内填部分混凝土箱形截面钢桥墩在恒定竖向荷载与柱顶水平往复荷载作用下的延性性能，建立三维弹塑性有限元模型，通过比较模拟结果与试验结果的水平荷载－水平位移滞回曲线和破坏模态，确定了所采用有限元分析方法的准确性与有效性。以翼缘宽厚比、柱长细比、混凝土填充率和柱轴压比为变化参数，建立56个三维弹塑性有限元分析模型，归纳总结了钢桥墩可能出现的各破坏模态：对于纯钢桥墩，局部屈曲发生在试件底部；对于内填部分混凝土钢桥墩，当混凝土填充率较小时，局部屈曲通常发生在内填混凝土上部钢板处；随着混凝土填充率的增大，局部屈曲出现在试件底部附近。最后分析上述4个参数对钢桥墩极限承载力和延性性能的影响规律。