时变空间路面模型建立及其对车-桥耦合振动的影响分析

Time-varying Inconsistent Stimulus Model of Surface Roughness and Analysis of Its Influence on Vehicle-bridge Coupling Vibrations

路面不平度模型是车-桥耦合振动分析的重要组成部分,路面不平度的横向分布及其劣化对分析结果影响较大。鉴于现有研究中对路面劣化进程中的车辆荷载时变因素及路面横向分布特征考虑不足,本文提出了一种时变空间路面非一致激励模型建立方法,并分析其对车-桥耦合系统的影响。首先,基于交通量发展特征及典型高速公路实测数据,建立车辆荷载时变模型;然后融合路面不平度劣化及轮迹横向分布规律,建立时变空间路面模拟方法;最后以一实桥工程为例对时变空间路面模拟过程进行分析,并研究其对车-桥耦合系统响应的影响。研究结果表明:提出的时变车辆荷载模型可以较好地反映交通量及车质量分布的演变规律;随着服役时间的增长,路面位移功率谱密度不断增大,路面横向位移呈凹凸分布,与累计轴载作用次数的分布相对应,桥梁冲击系数及车体加速度均快速增长,增长速率逐渐增大。采用提出的非一致激励路面模型时,桥梁冲击系数及车体加速度对车辆加载位置的变化较为敏感,基本表现为越靠近超车道,数值越小;非一致激励路面模型的冲击系数计算结果基本介于一致激励最差路面与最好路面之间;非一致激励路面模型对车体横向加速度的影响大于竖向加速度,且对横向加速度有放大效应。研究结论可对桥梁动力性能评估及冲击系数取值的制定提供参考。

The pavement roughness model plays a crucial role in vehicle-bridge coupled vibration analysis.The transverse distribution and degradation of pavement roughness have a substantial impact on the analysis outcomes.However,existing research often overlooks the influence of time-varying factors related to vehicular load during pavement deterioration and neglects the transverse distribution characteristics of the pavement.To address these limitations,this study proposes a method to establish a time-varying three-dimensional pavement model and investigates its effects on the vehicle-bridge coupled system.Firstly,a time-varying vehicular load model is developed based on traffic volume development law,and data are acquired from typical highways.By integrating the degradation of pavement roughness and the lateral distribution of vehicular trajectories,a simulation method for the time-varying pavement is established.An analysis is then conducted on a practical bridge engineering case to assess the influences of the simulation process on the response of the vehicle-bridge coupled system.The research findings demonstrate that the proposed time-varying vehicular load model effectively captures the evolution patterns of traffic volume and vehicular mass distribution.Over time,the displacement power spectral density of the pavement steadily increases.The transverse displacement of the pavement exhibits a concave-convex distribution pattern,which corresponds to the distribution of cumulative-equivalent axle loads.Notably,the impact coefficient and vehicular acceleration increase rapidly,yielding an increasing rate as time progresses.Utilizing the proposed non-uniform excitation pavement model reveals its sensitivity to changes in the vehicle loading position.Specifically,as vehicles approach the passing lane,both the impact coefficient and vehicular acceleration exhibit smaller values.The calculated impact coefficient obtained using the non-uniform excitation pavement model falls within the range between the worst and best cases of the uniform excitation pavement.Furthermore,the non-uniform excitation pavement model has a greater influence on lateral vehicular acceleration compared with that induced by vertical acceleration and causes an amplifying effect on lateral acceleration.These research findings provide valuable insights for assessing the dynamic performance of bridges and establishing appropriate impact coefficient values.