混凝土公路斜桥的动反应研究

Dynamic Response Research of Concrete Highway Skew Bridge

随着车辆质量、速度的逐渐增大和桥梁结构的逐渐轻柔化,车桥相互作用问题越来越受到关注。分别应用拉格朗日方程和模态叠加法建立三维非线性车辆模型和桥梁的振动方程,车轮与桥梁在接触点满足接触力和位移协调条件,利用迭代技术求解二者的相互作用问题。并以公路斜桥为分析对象,研究了不同斜交角、不同车辆行驶状态下以及不同行车速度情况下,横向不同梁的动挠度和动态增量。结果显示,斜交角、车辆行驶状态以及车速均是影响桥梁动反应的重要因素;当车辆行驶速度在30、40 km/h左右时,梁的动态增量达到最大;而且随着斜交角的增大,离车辆行驶位置越远的梁的动态增量也越大。

The vehicle-bridge interaction problem has been paid much attention in these years due to bridge structures getting gradually lighter and more flexible, while the speed and weight of moving vehicles are greater. The 3D nonlinear bridge and the vehicle are treated as two separate systems, dynamic equations have been developed with the help of Lagrange Formulation and mode superposition theory, to solve the two uncoupled sets equation for bridge and vehicle separately by an iterative procedure to satisfy the geometrical compatibility conditions and equilibrium conditions of the interaction forces between the bridge and the vehicle. The dynamic response of concrete highway skew bridges was investigated considering different skew angle, different traffic condition and different speed. Analytical results indicate that skew angle, traffic condition and speed are important factors for bridge＇s dynamic response and according to the parameters, bridge＇s dynamic increment （DI） will be up to its maximum when the vehicle speed at about 30-40 km/h and that with the increase of skew angle, bridge＇s DI of the girder which is far from the moving vehicle position will be much larger.