This study proposes a method for assessing the effect of stochastic vibrations resulting from track irregularities which are rarely studied but significant on bridge fatigue. First, the pseudo-excitation method is utilized to determine the power spectrum density of stress. Subsequently, the trigonometric series method is employed to acquire the stress time history set. Then, a traditional fatigue life calculation method is employed for analysis. By utilizing a post-sampling method, the need for costly repetitive solutions of the vehicle-bridge coupling system is eliminated. Numerical simulations are conducted on a steel truss bridge, revealing the non-negligible effect of track irregularity on bridge fatigue performance. The study investigates the underlying mechanism, highlighting the pronounced influence of long-wave track irregularity. Moreover, the research explores the correlation between track smoothness and bridge fatigue performance, demonstrating that a decrease in track smoothness leads to an increase in fatigue loss. These findings emphasize the necessity of considering stochastic vibrations when evaluating bridge fatigue, providing valuable insights for bridge design and maintenance.

这项研究提出了一种评估轨道不平顺引起的随机振动影响的方法，这种方法很少被研究，但对桥梁疲劳很重要。首先，利用伪激励法确定应力的功率谱密度。随后，采用三角级数方法获取应力时程集合。然后采用传统的疲劳寿命计算方法进行分析。通过利用后采样方法，无需对车桥耦合系统进行昂贵的重复解决方案。对一座钢桁架桥进行了数值模拟，揭示了轨道不平顺对桥梁疲劳性能的不可忽视的影响。该研究调查了潜在的机制，强调了长波轨道不规则性的显着影响。此外，该研究还探讨了轨道平滑度与桥梁疲劳性能之间的相关性，证明轨道平滑度的降低会导致疲劳损失的增加。这些发现强调了在评估桥梁疲劳时考虑随机振动的必要性，为桥梁设计和维护提供了宝贵的见解。