车桥随机振动作用下的桥梁动态影响线研究

将传统的静态影响线概念推广到动态影响线范围，研究了在车辆荷载和桥面随机不平度的作用下，简支梁桥和三跨弹性支承梁桥跨中挠度的动态影响线.基于虚拟激励法将桥面不平度转化为确定性的简谐激励，并采用精细积分法对车桥系统方程求解，获得了桥梁跨中挠度动态影响线的均值和标准差.基于 法则构造虚拟激励输出响应的确定值计算方法，获得了桥梁挠度动态影响线的确定性值域.最后通过算例分析了桥梁动态影响线的随机特性和车速与桥面不平度等级变化对桥梁动态影响线的影响，并研究了简支梁桥和弹性支承梁桥在随机振动作用下的动态影响线差异.

Dynamic Deflection Influence Line of Bridge Subjected to Vehicle Bridge Random Vibration

Traditional static influence line was developed into dynamic field, and dynamic influence lines of deflections in the mid span of a simply-supported bridge and a three-span elastically supported bridge were studied by considering the effect of interaction between the bridge, the bridge random surface roughness and the vehicle. To obtain the mean value and standard deviation of dynamic influence lines in the mid span of bridge, deterministic harmonic excitations were derived from bridge surface roughness with pseudo excitation method, and the equation of vehicle-bridge system was solved with precise integration method. Based on 3σ method, deterministic values range of dynamic deflections were obtained. Finally, the random characteristics of dynamic influence lines were analyzed with numerical examples, and the effects of vehicle velocity and bridge random surface roughness on dynamic influence line were discussed. Then the difference between the simply-supported bridge and the three-span elastically supported bridge was studied upon dynamic influence line.