连续宽箱组合梁桥混凝土桥面板的疲劳损伤度

Fatigue damage of concrete slabs in wide box continuous composite bridge

以杭州九堡大桥北引桥工程为背景,在已知疲劳设计车辆荷载模型的基础上,利用有限元法计算了车辆荷载下组合梁桥桥面板局部钢筋的应力历程.根据预测交通量,采用雨流法,换算得到了桥面板钢筋的应力谱,并用累计损伤准则得到了钢筋的疲劳损伤.对各车道在车轮局部荷载作用下钢筋的等效应力幅进行了对比,找到了最不利的车道受力位置,并对重车比例对混凝土桥面板的疲劳损伤的影响进行了比较.分析结果表明:如果仅按照静力标准设计,连续宽箱组合梁桥桥面板在100年设计使用期内出现疲劳破坏的可能性很大,设计时应充分考虑疲劳的影响,慢车道位置的合理布置以及减少重车的比例对桥面板的疲劳性能有显著的提高.

Based on the vehicle load model of fatigue design, the stress history of reinforcement in the concrete slab of northern approach of Jiubao Bridge with a multi-span continous composite bridge was obtained under vehicle load by finite element model. The stress spectrum of reinforcement was achieved by Rain-flow method according to the predicted traffic volume in the future of 100 years. Fatigue damage of reinforcement at different locations was achieved and compared to obtain the most disadvantageous place. The results show that fatigue failure of reinforcement may occur in deck slabs of steel-concrete composite bridges during service life, and the fatigue effect should be considered in the design. Reasonable lanes arrangement and small proportion of heavy truck are beneficial for fatigue performance of deck slabs.