系杆拱桥短吊杆疲劳损伤评估

Evaluation of Fatigue Damage of Short Suspender for Arch Bridge

钢管混凝土系杆拱桥短吊杆易发生断裂,引起严重的工程事故。基于ANSYS软件建立了石门水库特大桥的全桥空间精细化数值模型,并开展疲劳分析;考虑车辆类型、车辆行车的行车道、行车速度、车头距及轴重分布特征,编制了随机车流程序。对吊杆进行了影响线加载计算得到吊杆疲劳应力幅时程。基于钢绞线S-N曲线,采用雨流计算法,利用Miner线性累积损伤准则,评估短吊杆疲劳损伤度。研究结果显示：短吊杆100年时疲劳损伤度为0.795,表明如果仅仅考虑随机车流引起的疲劳损伤,其吊杆损伤度未超过1.0。

CFST arch bridge short suspender is easily broken,which can cause serious engineering accidents.Full bridge space fine numerical model of Shimen Reservoir Bridge is built based on ANSYS,and fatigue analysis is carried out based on the model.Taking into considerations of the vehicle type,vehicle lane,driving speed,headway and axle load distribution,random vehicle flow program is developed.The fatigue stress amplitude history of suspender is calculated by the influence line loading.Based on the S-N curve of steel strand,the fatigue damage degree of short suspender is calculated by using the method of rain flow calculation and the Miner linear cumulative damage criterion.The fatigue damage and fatigue life of the suspender under the vehicle fatigue load spectrum are evaluated.The results show that the fatigue damage degree of short suspender is 0.795 in 100 years,which shows that if the fatigue damage caused by random traffic flow is considered only,the damage degree of suspender is no more than 1.0.