交通事故状态下斜拉桥结构响应分析

Structural Response Analysis of Cable-stayed Bridges in Traffic Accidents

为实现交通事故状态下斜拉桥结构响应分析,首先,基于已有风车桥耦合分析系统,建立了不同车流密度的随机车流模型,并引入车流制动反应模型和不同交通事故状态,构建了交通事故状态下的风车斜拉桥耦合振动分析框架;其次,以沿海地区一市政斜拉桥为背景建立了有限元模型,并进行了主梁风场模拟加载;然后,对车流制动位置、车流密度进行了参数敏感性分析,分析了车辆制动的最不利位置和不利车流密度;最后,分析了不同交通事故工况下随机车流制动的桥梁关键位置最不利的结构响应区间。结果表明:车辆在中跨跨中制动时对桥梁关键位置结构响应影响显著,车辆制动对塔顶纵向位移、最长索索力影响显著大于梁端纵向位移和塔根弯矩;稀疏车流对纵向位移的影响显著大于一般车流和密集车流,而密集车流对弯矩和最长索索力的影响显著大于一般车流和稀疏车流;多车道事故状态下密集车流制动对桥梁结构影响较稀疏车流显著,正常运营状态和单车道事故状态下稀疏车流制动对桥梁结构纵向位移影响较密集车流显著。

In order to realize the structural response analysis of cable-stayed bridge under traffic accident condition.Firstly,based on the existing windmill bridge coupling analysis system,the random traffic flow model with different traffic densities is established,and the traffic flow braking response model and different traffic accident conditions are introduced to construct the analysis framework of the coupled vibration of windmill cable-stayed bridge under traffic accident condition.Secondly,based on a municipal cable-stayed bridge in coastal area,the finite element model is established and the main girder wind field is simulated.Then,the parameter sensitivity analysis of braking position and density of traffic flow is carried out,and the most unfavorable position and density of traffic flow are analyzed.Finally,the structural response interval of the bridge with random traffic flow braking is analyzed under different traffic accident conditions.The results show that the vehicle braking in the middle span has a significant influence on the structural response of the key position of the bridge,and the vehicle braking has a significant influence on the longitudinal displacement of the top of the tower and the cable force of the longest cable.The influence of sparse traffic flow on longitudinal displacement is significantly greater than that of general traffic flow and dense traffic flow,while the influence of dense traffic flow on bending moment and longest cable force is significantly greater than that of general traffic flow and sparse traffic flow.Under the condition of multi-lane accident,the influence of dense traffic braking on the bridge structure is more significant than that of sparse traffic,while under the condition of normal operation and single-lane accident,the influence of sparse traffic braking on the longitudinal displacement of the bridge structure is more significant than that of dense traffic.