正交异性钢桥面板顶板疲劳性能研究

Fatigue Research on Bridge Deck-plate of Orthotropic Steel Bridge Deck

为了给大桥的疲劳寿命评估、健康监测和养护维修提供依据,并为桥梁设计提供参考,以九江长江公路大桥正交异性钢桥面板、U肋和横隔板连接部位的顶板为研究对象,对实桥结构进行有限元分析,确定了能反映该细部结构受力状态的疲劳试样结构形式;根据对疲劳试样的模拟仿真和应力测试,确定了焊接细部结构顶板应力分布状况;通过对疲劳试样进行疲劳试验可得到该构造细节的疲劳破坏形式、Δσ-N曲线方程和容许应力幅。研究结果表明:该细节200万次疲劳寿命的容许应力幅值为95.93MPa;减小该细部焊接残余拉应力,避免焊根处发生疲劳裂纹可以提高其疲劳强度。

In order to provide basis for the evaluation of fatigue life, health detection and maintenance and repair of the bridge and provide reference for bridge design, the bridge deck- plates of U-rib, diaphragm and orthotropic steel bridge deck on Jiujiang Yangtze River Expressway Bridge were studied. Through finite element analysis of the real bridge structure, the fatigue specimen which could reflect stress state of the detail was determined. Based on the simulation and stress test, the stress distribution of the deck-plate was gotten. Fatigue failure form of the structure detail, △σ-N curve and allowable stress amplitude were obtained by the fatigue test. The results show that the allowable stress amplitude of the detail is 95.93 MPa at two million cycles. If the welding residual tensile stress of the detail is reduced and the fatigue crack is avoided in the weld root, the fatigue strength of the detail will be improved.