重载交通作用下某斜拉桥疲劳损伤研究

Study on Fatigue Damage of a Cable-stayed Bridge under Heavy Traffic

该文以某公铁两用斜拉桥为背景,引入基于热点应力的S-N曲线,对重载交通作用下考虑公铁联合作用的结构疲劳损伤进行了研究。文中通过交通量调查获得共35个交通量样本数据,根据等效损伤原理得到典型疲劳车型和车辆荷载谱,应用Monte-Carlo方法和Miner线性损伤准则计算了典型构造细节的损伤度;为研究重载交通的影响,考虑了各疲劳车型超载一定比例和仅某种车型超载两种情况,探讨了重载交通对结构构件损伤的影响。研究结果表明,按目前的交通状况预测,大桥疲劳寿命满足设计要求,随超载车数量占总交通量比例的增加,构件疲劳损伤度迅速增长,相比其它车型,5轴以上车辆超载时损伤度有了明显的增加。

Taking a highway-railway cable-stayed bridge as the background and introducing S-N curve based on hot spot stress,the article studies the structural fatigue damage considering the combined effect of highway and railway under heavy traffic.35 sample data of traffic volume are achieved by the investigation of traffic volume.The typical fatigue vehicle type and the vehicle load spectrum are achieved on the principle of equivalent damage.Monte-Carto method and Miner linear damage rule are used to calculate the damage level of the typical structure details.In order to study the influence of heavy traffic,the article considers two kinds of circumstances of various fatigue vehicle types with a certain proportion of over load and a vehicle type with a over load,and discusses the influence of heavy traffic on the structure damage.The study result makes clear that the fatigue life of bridge can satisfy the design requirement according to the forecast of the present traffic status.With the increment of the number of over-load vehicle in the percentage of total traffic volume,the fatigue damage level of structure quickly increases.Compared with the other vehicle types,the damage level of more than 5-axie vehicle will obviously increase during over load.