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