Wind Load And Structural Response Characteristics Of Bridge Sound Barrier Under Random Traffic Disturbance

The process of urbanization and economic development in China has driven the growth of large-scale urban viaduct construction and traffic travel,and the widespread installation of viaduct sound barriers has effectively blocked the traffic noise from interfering with residents’ lives.However,some in-service bridge sound barriers have suffered from abnormal vibration and damage at the bottom of the columns during their lifetime.As an important component of transportation infrastructure assets and total life-cycle cost,the mechanism of sound barriers and their service performance under the action of random traffic wind loads need to be urgently studied.At present,the research on sound barrier vehicle-induced wind load is mainly focused on high-speed railroads,and the research on mainly focuses on high-speed railroads,and there is little research on the vibration of sound barriers caused by road traffic,and there is a lack of research on the spatial and temporal characteristics,structural response analysis and long-term performance design methods of vehicle-induced wind loads on sound barrier under the road traffic condition.This study explores the integration of the deterministic vehicle disturbance and the randomness of traffic flow characteristics to establish a probabilistic expression method for the wind load and structural response of the sound barrier with random traffic disturbance,taking the roadside sound barrier as the representative.The numerical analysis tools for the vehicle-induced wind loads and structural response of the sound barrier are verified by the measured data and established to reveal the spatial and temporal distribution of the vehicle-induced wind loads and their spatial and temporal relationships with the structural response under the influence of multiple parameters,and the corresponding parametric models are given to establish the vehicleinduced wind load database.Based on the established numerical tools for structural response calculation,the vibration response characteristics of the sound barrier under the same physical process as the vehicle-disturbing wind are studied.Combined with computer vision,machine learning and traffic simulation technology,the identification and simulation extrapolation of traffic flow driving characteristics are realized,and probabilistic models of key parameters such as vehicle type,vehicle speed and vehicle screen distance are obtained;the random traffic disturbance wind load spectrum and stress probability model are constructed through data correlation,and the structural analysis of the sound barrier under the action of random traffic wind load is completed.The results will provide the support for the design of sound barriers on viaducts under the random traffic flow.The main research contents and innovations of this study are as follows.(1)The numerical simulation method of vehicle-induced wind load based on dynamic grid technology is validated and established by combining the full-scale field measurement tests of typical vehicles.The simulation analysis of the vehicle-induced wind loads of typical vehicles at different vehicle speeds and screen distances reveals that the main reason for the positive and negative pressure differences in the vehicleinduced wind loads of the sound barrier is due to the separation of air at the front,the flow along the vehicle body and the influence of the whole process of vortex release at the rear.Based on the validated numerical simulation method,we analyzed and obtained the single-vehicle moving flow field of typical vehicles and its interference mechanism with the sound barrier,established a parametric vehicle-induced wind load model for typical vehicles,and used it to construct a corresponding vehicle-induced wind load database,which provides a data basis and technical guarantee for the analysis of vehicle-induced wind load of random traffic.(2)Based on the measured traffic video data,the computer vision technology is used to generate the key driving characteristics parameters of the traffic flow,establish the vehicle driving characteristics database for the vehicle-induced wind load modeling,and construct the probability model of the key vehicle driving characteristics parameters in the vehicle-induced wind load.For the three key parameters of vehicle speed,vehicle type and vehicle-barrier distance of the vehicle-induced wind load,the probabilistic model of the driving characteristics under the measured traffic flow and the established vehicle-induced wind load database are fused by using the parameter association method,and the probabilistic model of the vehicle-induced wind load of the sound barrier under the random traffic flow and the probabilistic model of the response of the vehicle-induced wind load in the critical area of the sound barrier are formed.(3)The dynamic response characteristics of the sound barrier under vehicleinduced wind load are revealed through field tests and the finite element model,and a numerical method applicable to the dynamic simulation analysis of vehicle-induced wind load is proposed.Based on the refined finite element shell and solid cell model,the structural response of the sound barrier caused by the vehicle-induced wind load during the driving process is simulated and analyzed,and the spatial and temporal characteristics of the structural response of the sound barrier under the disturbance of the vehicle-induced wind load are revealed.Based on the numerical analysis method established in this study,the differences between the vibration response of the sound barrier under single-vehicle and multi-vehicle intersection are analyzed.The simplified calculation method of sound barrier structural response under the vehicle-induced wind caused by random traffic is also established based on a real city viaduct sound barrier.Through the finite element analysis of typical single-vehicle conditions,the probability model of sound barrier structural response under random traffic flow is established by combining the stress amplitude statistics and the probability model of key parameters with the Monte Carlo sampling method.Combined with the fatigue calculation theory of steel structure and the statistics of stress extremes in the control part of the steel column of the sound barrier,the fatigue evaluation method of wind vibration response of the vehicle-induced sound barrier is established,and the design suggestions of the sound barrier structure are given.