装配式组合连续刚构桥的负弯构件疲劳实验设计研究

Study on design of fatigue experiment of negative bending component of assembled continuous rigid frame bridge

为掌握钢-混凝土组合桥梁负弯矩区段的疲劳性能,按1/4缩尺比设计制作了装配式钢桁-混凝土组合模型实验梁,并考虑实桥正常使用状态和3倍车辆荷载超限状态下对组合梁进行了300余万次的疲劳荷载实验。实验结果表明,在正常使用(200万次)疲劳荷载作用下,实验梁处于弹性工作阶段,桥道板无开裂,状态良好;在3倍超限(310万次)疲劳荷载作用下,虽然预制桥道板已经出现开裂,但实验梁整体刚度尚可,PCSS剪力连接件滑移仍处于弹性阶段。实验结果为实桥的安全运营提供了有利参考。

In order to grasp the fatigue performance of the negative bending section,a fabricated steel truss-concrete composite model experimental beam is designed and made according to the 1/4 scale ratio.In consideration of the normal service state of the actual bridge and the three-times vehicle overload condition,the fatigue load experiment of the composite beam has been carried out for more than three million times.The experimental results show that under the normal use（two million times）fatigue load,the experimental beam is in the elastic working stage,and the bridge slab has no crack and is in good condition.Under the action of the three times over-limit（three hundred and ten million times）fatigue load,although the prefabricated bridge slab has been cracked,the stiffness of the experimental beam is still available,and the slip of the PCSS shear connector is still in the elastic stage,which provides the favorable reference for the safe operation of the real bridge.