水平往复荷载作用下自复位圆形钢桥墩力学性能研究

Study on Mechanical Properties of Self-centering Circular Steel Piers under Lateral Cyclic Loads

目的 探究自复位独柱式圆形钢桥墩在水平往复荷载作用下的力学性能,提高桥梁的抗震能力。方法 通过对某桥墩试件建立数值分析模型,并与试验结果进行对比,验证桥墩有限元模型的有效性;在此基础上,改变径厚比、长细比以及预应力比等参数,建立20个自复位圆形钢桥墩有限元模型,在恒定轴力和水平往复荷载作用下进行弹塑性分析,探究径厚比、长细比以及预应力比对自复位圆形钢桥墩的最大承载力和残余位移等抗震性能的影响,并通过理论分析给出简易的力学计算方法。结果 增加径厚比,桥墩承载能力、复位能力均降低;增加长细比,桥墩的承载能力和复位能力也降低;增加预应力钢绞线的预应力比,桥墩的复位能力降低,但承载能力提高。结论 合理地控制长细比、径厚比和预应力比可以使该类桥墩具有较好的变形能力和复位能力,笔者推导所得的计算方法对工程实际具有很好的指导意义。

In order to explore the mechanical performance of self-centering single-column circular steel piers under lateral cyclic loading and improve the seismic performance of bridge,the finite element(FE)models of self-centering steel piers were established referring to the previous tests.The results obtained from FE analyses are in good agreement with the experimental results,demonstrating the numerical models are reasonable and effectively.Subsequently,by adjusting the radius-to-thickness ratio,slenderness ratio,and the prestressing stress ratio,a total of 20 FE models of self-centering steel piers were built.Under the constant axial force and lateral cyclic load,the elastic-plastic analysis was carried out,and the influence of the radius-to-thickness ratio,slenderness ratio,and the prestressing stress ratio on the ultimate force capacity,residual displacement of self-centering steel piers is investigated.A simple mechanical calculation method is given through theoretical analysis.From the FE results,it can be found that,with the increase of radius-to-thickness ratio and slenderness ratio,the ultimate strength and recovery capacity of self-centering steel piers will degrade.However,as the prestressing stress ratio increases,the strength of piers will increase,while the recovery capacity will degrade.Based on the research results,a reasonable control of slenderness ratio,radius-to-thickness ratio and the prestressing stress ratio can improve the ability to withstand deformation for this type of bridge pier and its recovery capacity,and the calculation method of its mechanical property can provide guidance for engineering practice.