钢桁加劲梁悬索桥耳板节点抗疲劳性能研究

Fatigue Performance of Ear-plate Joints in Steel Truss Stiffened Suspension Bridge

针对钢桁加劲梁悬索桥中的耳板节点存在应力集中,疲劳性能不明确的问题,对贵州坝陵河大桥钢桁加劲梁耳板节点进行足尺比例的疲劳模型试验。参考BS5400及AASHTO设计规范中疲劳设计的有关规定,考虑未来交通量的发展,计算得到耳板节点对应于200万次循环加载的内力幅。采用MTS全自动液压伺服疲劳试验机进行加载试验,研究了钢桁加劲梁耳板节点应力分布特点及关键构造细节的抗疲劳性能。研究结果表明,该结构部分区域存在一定程度的应力集中,在设计疲劳荷载幅作用下,关键构造细节应力幅水平不高,经循环加载疲劳试验结构关键部位未发现疲劳裂纹,耳板节点的抗疲劳性能满足设计要求,并具有一定的安全储备。

In order to investigate the mechanical behavior and fatigue reliability of ear plate joint in steel truss stiffened suspension bridges,a full-scale fatigue model test of the ear plate joint of Baling River Bridge(a suspension bridge with steel truss girder in Guizhou Province,China) were performed.Based on the estimative vehicle traffic of Baling River Bridge in future,according to the rules of the AASHTO LRFD Bridges specifications and the British Standard Institution BS5400,fatigue load range of ear plate bearing 2×106 load cycles was calculated.MTS automobile hydraulic servo control system was used for fatigue experiment to investigate the stress distribution on ear plate joint and fatigue performance of key structural details.The test results show that there exist stress concentrations in local areas,no fatigue cracks were found on important position of ear plate joint after 2×106 cyclic loading.The fatigue performance of ear plate meets the need of design and it is reliable in service lifetime.