考虑桥面随机不平顺的桥梁动态响应研究

基于随机振动理论研究了桥面不平顺影响下，车桥耦合振动作用时的中小桥梁动态响应曲线。通过建立车桥耦合振动方程，基于虚拟激励法对重力引起的确定性激励和桥面不平顺引起的随机激励求解，得到了桥梁跨中挠度和应力响应的均值和标准差。运用 法则定义随机激励的确定值值域，分析了桥梁跨中位移和应力响应在不同车速和桥面不平顺等级作用下的特性，并讨论了动态响应曲线与准静态影响线的差异。结果表明：桥梁跨中挠度和应力标准差受车速和桥面不平顺等级变化的影响很大；桥梁动态响应值域范围很大，具有较强的随机性；相比准静态影响线，动态响应曲线更能体现车桥之间激励的耦合随机作用。

Dynamic response of bridge considering bridge surface random roughness

Based on random vibration theories, curves of dynamic response of short and medium-span girder bridges under vehicle-bridge coupling vibrations were studied, with considering bridge surface roughness. The dynamic equations of vehicle-bridge coupling systems were solved using the Pseudo-Excitation Method (PEM), and statistical values and standard deviations of deflection and stress of bridge are calculated conveniently. Based on the  method, the statistical solutions can be transformed into deterministic values range, which were paid more attention by engineering community. The results show that standard deviation of deflection and stress in the mid span of bridge is greatly affected by vehicle velocity and randomly uneven bridge surface grade, and the dynamic influence lines of bridge are value range and significantly random characteristics. Compared with the quasi-static influence line, the curve of dynamic response reflects the interaction of vehicle-bridge more evidently.