钢梁桥竖向弹塑性地震反应分析的非线性位移系数法  

Inelastic Displacement Ratio Approach for Analyzing the Vertical Elasto-plastic Seismic Responses of Steel Beam Bridges

作　　者：尹剑 YIN Jian(Shanxi Transportation Research Institute Group Co.,Ltd.Taiyuan 030006,China)

机构地区：[1]山西交通科学研究院集团有限公司,太原030006

出　　处：《太原理工大学学报》2021年第3期456-465,共10页Journal of Taiyuan University of Technology

摘　　要：钢梁桥在竖向地震作用下的弹塑性变形在"向下"方向累积,在"向上"方向结构保持弹性。基于此,建立了钢梁桥在竖向地震作用下的非对称滞回模型。采用53条近场竖向强震记录和自编非线性动力反应分析程序,计算了钢梁桥在竖向地震作用下的弹塑性位移需求。结果表明:钢梁桥等效竖向屈服强度越高,或其屈服后刚度系数越高,钢梁桥的弹塑性位移需求越低,离散性越小。基于计算结果,拟合得到了钢梁桥在竖向地震作用下的弹塑性位移系数公式。采用该方法计算一个钢桁架梁桥在竖向地震作用下的弹塑性反应,所得结果与时程分析结果吻合。对于跨中竖向位移,误差不超过11%;对于屈服构件数量和位置,本文方法与时程分析方法结果一致。The inelastic deformation of a steel beam bridge under vertical seismic actions would accumulate in the“downward”side,whereas in the“upward”side,the structure keeps elastic.An un-symmetric hysteretic model was established for the steel beam bridge subjected to vertical earthquake actions.By using 53 strong vertical earthquake records and a developed nonlinear dynamic analyzing code,the inelastic displacement demand of steel beam bridges under vertical seismic actions were computed.From the results,a higher equivalent vertical yield strength or a larger post-yield stiffness ratio would lead to a smaller inelastic seismic demand for steel beam bridges,as well as a decreased dispersion in the demand.Based on the numerical results,a formula for the inelastic displacement demand of steel beam bridges under vertical seismic actions was proposed.The proposed vertical inelastic displacement ratio approach was adopted to calculate the seismic responses of a steel truss beam bridge under vertical seismic excitations,the results obtained agree well with those given by the nonlinear response history analysis.For mid-span vertical displacement,the error of the result is less than 11%.For the quantity and the location of yield members,the results of the proposed approach are identical with those given by the response history analysis.

关 键 词：桥梁结构 竖向非线性位移系数 非线性地震反应分析 钢梁桥 竖向非对称滞回 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]