钢桥面板焊缝疲劳裂纹扩展规律与开裂失效机理研究

项目名称： 钢桥面板焊缝疲劳裂纹扩展规律与开裂失效机理研究

项目编号： No.51478163

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 建筑科学

项目作者： 吉伯海

作者单位： 河海大学

项目金额： 84万元

中文摘要： 我国大跨径钢桥规模和数量已处于世界前列，随着已建钢桥服役年限的增长，钢桥面板疲劳问题日益突出，成为钢桥运营安全亟需解决的难题之一。疲劳开裂失效判定是钢桥疲劳维护的理论基础，而目前失效判定主要依赖经验。本研究通过试验和理论分析，探究钢桥面板疲劳开裂扩展规律，考虑裂纹干涉效应对承载力退化规律影响，提出疲劳开裂后失效评判方法。首先，应用新型振动疲劳试验机进行构件疲劳试验，结合残余应力和金相特征，分析裂纹扩展和失效模式，研究疲劳裂纹扩展规律。其次，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，研究开裂扩展过程中构件承载性能退化规律。再次，考虑多裂纹的共同作用，进行多裂纹试件试验和数值分析，研究多裂纹间的干涉效应对承载性能的影响。最后，基于承载性能的退化规律，考虑实际工程的承载需求，提出钢桥面板疲劳焊缝失效评判标准。本研究可为疲劳开裂结构局部失效以及合理修复时机评判提供理论依据。

中文关键词： 钢桥面板；疲劳；裂纹扩展；失效机理；多裂纹

英文摘要： China's long span steel bridges are at the leading position in the world considering either scale or amount. As the prolong of service life of the domestic built steel bridges, the fatigue problems of the steel bridge deck become increasingly prominent, which also being one of the difficult issues for the safe operation of the bridges. And failure evaluation of the fatigue crack is the theoretical foundation of the fatigue maintenance of steel bridge. Bt it mainly based on experiences at present. By experiments and theoretical analysis, the propagation law of the fatigue crack will be studied. The deterioration of the partial bearing capacity of the structure will be analyzed, considering the interference effect of several cracks. The failure evaluation method for the fatigue crack will be put forward. First, fatigue experiments will be carried out on specimens with a new type of fatigue testing machine. Combining residual stress analysis and metallurgical analysis, the pattern of crack propagation and failure will be analyzed, and developed fatigue crack propagation law will be studied. Second, numerical simulation will be carried out toward the specimens stress regarding to the fatigue crack propagation process. Considering the test results, the deterioration law of the bearing capacity will be studied during the crack propagation process.Third, the specimens will be tested and analyzed considering multiple fatigue cracks, the interference effect of multiple fatigue cracks will be studied toward bearing capacity. Last, based on deterioration law of the bearing capacity, the evaluation criteria of the fatigue crack failure of the steel bridge deck will be proposed considering the demand of the actual project. The study can support and provide a theoretical background for the failure of the fatigue crack and determination of the appropriate repairing opportunity.

英文关键词： Steel bridge deck;fatigue;crack propagation;failure mechanism;multiple cracks