中文摘要：

为评定公轨两用钢桁桥下层轨道横梁与焊接整体节点连接头在交通荷载作用下的疲劳损伤累积，对该细节在桥梁设计寿命内车辆荷载所产生的疲劳荷栽谱的计算方法进行了研究。在对桥梁的车辆荷载进行分析的基础上，参照各国相关规范，建立了代表桥梁设计寿命内真实运营状况的疲劳荷载模型，并通过全桥三雏有限元分析模拟计算该连接细节所承受的荷载历程。依据疲劳损伤累积理论，确定了公轨两用钢桁桥轨道横梁与整体节点连接头验证性疲劳试验的试验荷栽。结果表明：该连接细节的疲劳损伤荷载基本不受上层汽车的影响，主要取决于轻轨，可以通过直接将轻轨计算结果乘以一定的提高系数得出。

英文摘要：

In order to estimate the fatigue damage accumulation of the connections between low layer rail across beams and welded integral joints connection of combined steel truss bridges under the traffic load, calculated method of fatigue load spectrum at the connection produced with the vehicle load in life-time of bridge design was analyzed. Based on analysis of vehicle load in bridge with reference to code in the world, the fatigue load model which could reflect the actual running state in life-time of bridge design was developed. The 3-D finite element analytical bridge model was used to simulated the load history at the connection. According to fatigue damage accumulation theory, test load of verified fatigue test on rail across beam and welded connections with integral joint of combined steel truss bridge was gotten. The results indicate that the fatigue damage load effects of trucks are negligible compared with light rail vehicles at the connections; fatigue load could be calculated with product between load of light rail and increasing coefficient.