车流作用下大跨度拱桥车桥耦合振动分析

Vehicle-bridge coupling vibration analysis of long-span arch bridge under the action of traffic flow

为更好开展大跨度钢管混凝土拱桥的设计与施工,提高司乘人员的舒适性,开展多车辆交通流工况下基于桥面不平顺的车桥耦合振动响应研究。以三轴货车和茅草街钢管混凝土拱桥为背景,通过有限元法建立桥梁的三维结构分析模型,基于动力平衡原理建立车辆的9自由度多刚体动力学模型。运用MATLAB模拟桥面不平顺,以车轮与桥梁接触面为界,利用车、桥2个子系统的位移协调条件及力的协调条件,用Newmark-β法求解车桥系统的振动微分方程。基于有限元分析软件ANSYS编制APDL迭代求解命令流,编写基于车桥耦合理论的车桥耦合振动分析程序。在车速、车重和车距等因素保持不变的情况下,计算多车辆交通流作用下路面不平顺对桥梁跨中节点、跨中截面、主拱拱顶及主拱1/4处等关键部位动力响应的影响,计算路面不平顺对车辆动力响应的影响。研究结果表明:当路面不平顺度增加时,桥梁跨中节点竖向振动位移峰值、加速度峰值呈非线性增长,桥梁跨中截面振动弯矩、正应力和剪应力峰值呈非线性增长;主拱拱顶及主拱1/4处的轴力、正应力及剪应力峰值呈非线性增长;桥梁的结构响应均在容许范围内。车辆竖向、侧倾和俯仰等3个自由度对应的位移峰值、加速度峰值均逐渐增大。研究结果可为以后开展大跨度拱桥结构设计、施工与维护工作提供有益借鉴。

In order to better study the design and construction of long-span concrete-filled steel tubular arch bridge,improve the comfort of drivers and passengers,and analyze the coupled vibration of vehicle and bridge based on bridge deck irregularity under the condition of multi-vehicle traffic flow.The three-axle truck and Maocaojie concrete-filled steel tube arch bridge were taken as the engineeringbackground,the three-dimensional structural analysis model of the bridge was established based on the finite element method,and the 9-degree-offreedom multi-rigid-body dynamic model of the vehicle was established based on the principle of dynamic equilibrium.The bridge deck irregularity was simulatedbased on MATLAB®,the interface between the wheel and the bridgewas takenas the boundary,and the displacement and force continuity conditions of the vehicle and bridge subsystemswere used to solvethe differential vibrationequation of the vehicle-bridge system by the Newmark-βmethod.The APDL iterative solution command flow was compiled based on the finite element analysis software ANSYS,and the vehicle-bridge coupled vibration analysis program based on the vehicle-bridge coupling theory was coded.The effect of pavement unevenness on the dynamic response of key parts of the bridge such as the mid-span node,mid-span section,the top of the main arch,the 1/4 of the main arch,and the effect of pavement unevenness on the dynamic response of vehicles were calculated with the factors of vehicle speed,vehicle weight and vehicle distance kept constant.The results show that when the road roughness increases,the peak values of displacement and acceleration of bridge mid-span node increase nonlinearly;the peak values of vibration moment,normal stress and shear stress of bridge mid-span section increase nonlinearly;the peak values of axial force,normal stress and shear stress at the top of the main arch and 1/4 of the main arch increase nonlinearly;the structural responses of the bridge are all within the tolerance range.The peak displacement and peak acceleration corresponding to the three degrees of freedom,such as vertical,lateral tilt and pitch of the vehicle,gradually increase.The results of the study can provide useful reference for the design,construction and maintenance of large-span arch bridge structures in the future.