以江阴长江大桥为研究对象，建立正交异性钢桥面板局部有限元模型，计算各种标准疲劳车作用下U肋对接焊缝处的疲劳应力幅，结合BS5400规范得到该细节相应位置的疲劳损伤度；建立车辆轮迹分布模型，将影响疲劳损伤的各参数矩阵化，根据实桥车流模拟结果，提出一种考虑轮迹改变的疲劳损伤计算方法。结果表明，U 肋对接焊缝腹板处的损伤相对较小，靠近顶板部位、腹板与底板交接部位，以及U肋底部的损伤较为严重；考虑车辆轮迹改变后的疲劳寿命与实测结果吻合度较高，因此考虑车辆轮迹位置的改变可以提高寿命评估的精确度。%The Jiangyin Yangtze River Bridge is studied in this paper .The local finite element model of orthotropic steel bridge deck is established .The fatigue stress amplitude of U‐rib butt weld under all kinds of standard vehicle loads is calculated and thus the fatigue damage degree of a certain position is obtained according to the specification BS5400 .Then ,the vehicle wheelmark distribution model is built up .By matrixing all parameters that affect the fatigue damage and considering w heelmark chan‐ges ,a fatigue damage calculation method is proposed based on the simulation results of traffic flow . The results show that the damage of U‐rib web butt weld is relatively less while that near the roof ,of web‐floor joint and of U‐rib floor is more serious .In addition ,the fatigue life of U‐rib butt weld by considering wheelmark changes matches well with the measured results .Therefore ,the accuracy of fatigue assessment could be improved by considering w heelmark changes in the calculation of fatigue lif e .
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