车桥耦合振动下中承式拱桥吊杆汽车冲击效应  

Vehicle Impact Effect of Suspender in Half-through Arch Bridge Considering Vehicle-bridge Coupled Vibration

作　　者：贺煊博 郭增伟 徐华 HE Xuanbo;GUO Zengwei;XU Hua(School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]重庆交通大学土木工程学院,重庆400074

出　　处：《噪声与振动控制》2022年第1期206-213,共8页Noise and Vibration Control

基　　金：国家自然科学基金资助项目(51878106);重庆市自然科学基金面上资助项目(cstc2019jcyj-msxmX0818);重庆市研究生联合培养基地建设资助项目(JDLHPYJD2020023);桥梁工程结构动力学国家重点实验室开放基金联合资助项目(编号:201501)。

摘　　要：针对中承式拱桥短吊杆在实际工程中易疲劳断裂的问题,采用接触约束法实现车桥耦合振动响应的求解,以某中承式拱桥为背景研究不同类型车辆过桥时不同长度吊杆轴力的时变特性和动力冲击效应,对比分析出、入桥侧短吊杆冲击效应的差异和不同部位吊杆的疲劳损伤分布规律。研究发现:车辆过桥时吊杆最大的力学响应出现在车辆通过该吊杆时刻,但吊杆轴向应力会出现波动,且应力波动的高频分量多发生于车辆经过吊杆后的余振阶段;车桥耦合振动所导致的吊杆轴向应力波动频率和幅值随吊杆长度的减小而逐渐增强,相同条件下算例最短吊杆的疲劳损伤度为最长吊杆的3倍;出桥侧主梁因受车辆荷载激励“方向性”的影响,导致出桥侧短吊杆的轴向应力冲击系数达到入桥侧短吊杆的2倍,且出桥侧吊杆的疲劳损伤度和疲劳动力放大系数均表现出大于等长度入桥侧吊杆的趋势;吊杆的疲劳损伤度随着车重的增加而增加,46 t车辆作用下短吊杆疲劳损伤度可达到2 t车辆的40000倍以上。The problem of fatigue fracture of short suspenders of half-through arch bridge is studied.Taking a half-through arch bridge as the research background,the vehicle-bridge coupled vibration response of the bridge is solved using the contact constraint method.The time-varying characteristics and dynamic impact effect of suspenders with different lengths and different types of vehicles passing through the bridge are studied.The difference of the impact effects on the short suspenders at the bridge exit side and entrance side and the distribution of fatigue damage of suspenders in different positions are analyzed.It is found that the maximum mechanical response of the suspender occurs when the vehicle passes through the suspender,but the axial stress of the suspender fluctuates,and the high frequency component of the stress fluctuation occurs in the residual vibration stage after the vehicle passes through the suspender.The frequency and amplitude of the axial stress fluctuation of the suspender induced by the vehicle-bridge coupled vibration increase gradually with the decrease of the suspender’s length.Under the same conditions,the fatigue damage degree of the shortest suspender is triple of that of the longest suspender.Due to the influence of direction effect of vehicle load excitation on the main beam on exit side of the bridge,the axial stress impact coefficient of the short suspender on the bridge exit side is twice of that of the short suspender on the bridge entrance side.And the fatigue damage degree and fatigue dynamic amplification coefficient of the suspender on the bridge exit side are greater than those of the suspender on the bridge entrance side with the same length.The fatigue damage degree of suspender increases with the increase of vehicle weight.The fatigue damage degree of the short suspender under the action of 46 t vehicle can be up to above 40000 times of 2 t vehicle.

关 键 词：振动与波 中承式拱桥 短吊杆 车致振动 冲击效应 疲劳损伤 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]