考虑桥面随机不平顺的桥梁动态响应研究

Dynamic response of a bridge considering its surface random roughness

基于随机振动理论研究桥面不平顺影响下,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,得到桥梁跨中挠度和应力响应的均值和标准差。运用3σ法则定义随机激励的确定值值域,分析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。

Based on the random vibration theories,dynamic response curves of short and medium-span girder bridges considering vehicle-bridge coupling and bridge surface rough ness were studied. The dynamic equations of the vehicle-bridge coupled system were solved using the pseudo-excitation method（ PEM）,and the mean values and standard deviations of the deflection and stress of the bridge＇s were calculated. Based on the 3σ method,the statistical solutions were converted into deterministic value ranges,attracted by attention of engineering researchers. The results showed that the standard deviations of the deflection and stress at the mid span of the bridge are greatly affected by vehicle velocity and bridge surface roughness level; the value range for the bridge＇s dynamic response is large and more strongly random;compared with the quasi-static influence line,the dynamic response curves reflect the interaction of vehicle-bridge more evidently.