钢桥面板纵肋与横隔板连接疲劳损伤机理与加固方法研究

纵肋与横隔板连接是控制钢桥面板耐久性的关键构造细节，轮载作用下应力传递复杂，构造设计不当极易引起疲劳裂纹。钢桥面板疲劳裂纹检查和修复困难，开裂后对行车平稳性甚至桥梁结构的安全性产生不利影响，且开裂后的修复代价巨大。本项目拟采用疲劳试验、数值模拟和理论分析方法对纵肋与横隔板连接的疲劳损伤机理和加固方法进行研究。首先，进行构件疲劳试验，明确移动轮载作用下纵肋与横隔板连接的关键细节位置和疲劳失效模式；其次，考虑焊接残余应力场和荷载引起的面外变形影响，对疲劳裂纹扩展过程中构件受力进行数值模拟。结合试验结果，揭示关键细节的疲劳开裂机理和裂纹扩展规律，并分析多裂纹耦合效应对钢桥面板承载性能退化规律的影响；最后，研究粘贴CFRP板对不同裂纹形式的加固效果，提出纵肋与横隔板连接疲劳开裂加固方法。

The rib-to-diaphragm joint is the key structural detail that controls the durability of the steel bridge deck. Fatigue cracks are easy to occur in this joint because of complex stress transfer and improper structural design. It is difficult to inspect and repair the fatigue cracks in orthotropic steel deck, and the cracks have adverse effects on the traveling stability and even the safety of bridge structure. In addition, the repair cost after cracking is huge. Based on fatigue test, numerical simulation and theoretical analysis, fatigue damage mechanism and reinforcement method of the rib-to-diaphragm joint will be studied. Firstly, the fatigue tests of the specimens are carried out to identify the location of the key details and the fatigue failure mode of the rib-to-diaphragm joint under the action of moving wheel loads will be obtained from the research. Secondly, a numerical simulation method considering the influence of the welding residual stress and the out-of-plane deformation, will be presented to reproduce the fatigue crack propagation process of the specimen under loading. Combined with the test results, the fatigue cracking mechanism and the crack propagation rule of the key details will be revealed, and the influence of multi-crack coupling effect on the degradation of bearing capacity of orthotropic steel deck will be analyzed. Finally, according to the different crack forms that may appear, the strengthening effect of pasted CFRP plates will be studied, and the fatigue cracking reinforcement method of the rib-to-diaphragm joint to will be put forward.