【摘要】 介绍国内首座大跨度公轨两用桥——重庆菜园坝长江大桥轨道横梁与整体节点连接的足尺模型疲劳试验。首先根据大桥交通状况与设计流量,由疲劳损伤累积理论,确定其疲劳荷载谱,制定出疲劳荷载取值;然后,设计并制作了1∶1足尺模型,对模型进行200万次疲劳加载试验。试验结果表明,试验模型应力水平较低,实测应力幅大致为30 MPa,疲劳加载200万次后,试验模型未出现裂纹。最后根据疲劳试验结果及国内外有关规范,对轨道横梁与整体节点连接的疲劳性能进行了评价,认为在结构使用寿命期间及正常养护维修情况下,该连接不会发生疲劳开裂,疲劳强度满足要求。更多还原

【Abstract】 The full-scale fatigue test of the connection structural details between track cross beams and monolithic joints in the Chongqing Caiyuanba Yangtze-river Bridge,the first long-span rail-cum-road bridge in China,is introduced.Firstly,the fatigue load spectrum and fatigue load value are decided using the cumulative fatigue damage theory based on the transportation situation and programming traffic.Then,the 1∶1 scale model is designed and produced;the fatigue testing of 2-million-cycle loadings on the model is carried out.Results show that the stress of the test model is relatively low and the field-testing stress amplitude is about 30MPa.And there are no visible cracks on the testing model after applying 2-million-cycle fatigue loadings.Finally,the fatigue behavior of the connection between track cross beams and monolithic joints is evaluated according to the fatigue testing results and corresponding fatigue design criteria existing inside and outside China.It can be seen that the connection structures between the track cross beams and monolithic joints will not be cracked by fatigue during the period of the structure lifespan and under normal maintenance.And the fatigue strength meets the requirements,the connection structure is reliable.更多还原