桁梁断面对大跨度公铁两用桥梁风-列车-桥耦合振动特性的影响

Influence of Truss Section on Wind⁃Vehicle⁃Bridge Coupling Vibration Characteristics of Long Span Rail⁃cum⁃Road Bridge

为研究不同桁梁断面形式对行车安全的影响,对一座大跨度跨海公铁两用桥梁6种断面进行数值模拟研究车-桥的气动特性,并与类似断面的风洞试验结果进行对比。通过刚度等效对主梁模型进行简化,缩减了桥梁模型的自由度,并与精细化的板壳模型进行对比验证。通过风-车-桥耦合振动分析,研究不同风速及车速条件下不同桁梁断面车辆及桥梁的响应,讨论双车交会的影响。结果表明:断面形状显著影响车桥气动特性,进而改变车辆和桥梁振动响应。与倒梯形断面相比,通过带挑臂断面或矩形断面时车辆及桥梁响应较小,一定范围内改变入桥距离差会明显改变桥梁产生的响应,但车辆响应受入桥距离差影响不大。

In order to study the influence of different girder section forms on traffic safety,six sections of a long span sea-crossing rail-cum-road bridge were numerically simulated to study the aerodynamic characteristics of the vehicle-bridge,and compared with the wind tunnel test results of similar sections.The main girder model was simplified by stiffness equivalence,and the degree of freedom of the bridge model was reduced,and compared with the refined plate and shell model.Through the analysis of wind-vehicle-bridge coupling vibration,the response of vehicles and bridges with different truss sections under different wind speeds and speeds was studied,and the influence of two trains passing each other was discussed.The results show that the section shape significantly affects the aerodynamic characteristics of the vehicle and bridge,and then changes the vibration response of the vehicle and bridge.Compared with the inverted trapezoidal section,the response of vehicles and bridges is smaller when passing through the section with cantilever arm or rectangular section.Changing the distance difference of entering the bridge within a certain range will significantly change the response of the bridge,but the vehicle response is not affected by the distance difference of entering the bridge.