考虑铺装层耦合效应的钢桥面板疲劳损伤机理研究

With the ever increasing of the steel bridge construction, China has taken the leading role in the manufacture of steel bridge for both the scale and quantity. However, the fatigue problem of the steel bridge is increasingly prominent over the time of operation and has become one of the main problems that need to be addressed in the field of bridge engineering in China. The current investigations aimed at the fatigue performance of the steel bridge deck only take the simple superposition of the stiffness of the the deck itself or the deck pavement into consideration regardless of the coupling effect of the deck pavement, resulting in errors of the fatigue property assessment results. The aim of this research is to investigate the fatigue mechanism in steel bridge considering the coupling effect of the deck and the pavement through fatigue experiments and theoretical analysis. Firstly, the basic mechanics experiment of layer connected with bridge deck and pavement will be carried out to investigate the law of stress transmission of the layer in combination with theoretical analysis. Secondly, the experiment of the test specimens with deck pavement will be carried out and contrasted with the result of traditional fatigue experiment to analyze the effects of each parameter to the fatigue performance of the steel bridge deck. Thirdly, the law of fatigue damage and the fatigue strength based on the coupling effect will be analyzed. Finally, the fatigue analysis model considering the coupling effect of the steel bridge deck and the deck pavement will be established and modified based on the test results. The research could serve as reference for the accurate assessment of fatigue property of the deck of steel bridge and the parameter design of the deck pavement.

我国钢桥的建设规模和数量世界领先，且在不断增加。随着运营时间的增长，钢桥疲劳问题日益凸显，已成为我国桥梁领域亟需解决的难题之一。目前针对钢桥面板疲劳性能的研究，大多仅考虑钢桥面板本身或铺装层刚度的简单叠加，尚未考虑铺装层耦合效应，导致疲劳性能评估结果存在较大误差。本研究基于疲劳试验和理论分析，考虑钢桥面板和铺装层整体耦合效应，研究钢桥面板的疲劳机理。首先，进行铺装和钢桥面板黏结层的受力试验，结合理论分析，研究黏结层的受力传递规律。其次，开展带铺装的钢桥面板试件疲劳试验，并与传统的疲劳试验结果对比，分析各参数对钢桥面板疲劳性能的影响规律。再次，分析耦合效应下的疲劳损伤规律和疲劳强度。最后，基于试验结果，建立钢桥面板与铺装层疲劳耦合分析模型，并对其进行修正。研究成果可为钢桥面板疲劳性能精确评估及铺装层参数设计提供参考。

正交异性钢桥面板因其卓越的受力性能在国内外得到了广泛应用。但在复杂的运营环境下，钢桥面板疲劳开裂问题普遍存在且难以避免。钢桥面板疲劳损伤的精确评估已成为当前面临的关键共性难题之一。除受结构构造、焊接残余应力、车辆荷载等因素影响外，铺装层对钢桥面板疲劳性能的影响不可忽视。但目前铺装层对钢桥面板疲劳性能的影响机理尚不明确，且缺乏考虑铺装层耦合效应的疲劳损伤评估模型，难以精确、有效地开展钢桥面板疲劳损伤的评估工作。.本项目在大量国内外调研的基础上，采用理论分析、数值模拟、试验研究、现场测试等手段，重点围绕铺装层影响机理及考虑铺装层耦合效应的疲劳损伤评估模型开展了研究。首先，利用弹簧单元模拟铺装层与钢桥面板间的界面粘结状态，分析了铺装层泊松比、弹性模量、厚度及铺装层与钢桥面板界面连接切向刚度等不同参数对钢桥面板焊缝受力的影响。建立了钢桥面板-铺装层复合梁的离散元模型及有限元模型，分析了荷载在铺装层内的扩散机理，探讨了温度、桥面板支撑刚度、板件厚度对荷载扩散效应的影响。从动载作用、轮载扩散效应两个角度对钢桥面板焊缝应力的变化特征进行了分析，并探讨了轮载扩散效应对钢桥面板疲劳损伤特征的影响。在此基础上，基于有效缺口应力法分析了钢桥面板疲劳裂纹萌生位置、有效缺口应力变化特征等，研究了考虑铺装层耦合效应的钢桥面板疲劳损伤特征。为实现考虑铺装层耦合效应的疲劳损伤精确评估，基于全空间S-N曲线的概念及有效缺口应力法提出的新的疲劳损伤评估框架，并分别基于顶板-U肋试件的疲劳试验结果及实桥测试数据对该疲劳损伤评估框架的合理性、可行性进行了验证。研究成果进一步揭示了铺装层对钢桥面板疲劳损伤的影响机理，提出了考虑铺装层耦合效应的疲劳损伤评估模型，可为钢桥面板疲劳损伤的科学评估提供支撑。