Research On Vehicle-bridge Coupled Dynamic Response And Influencing Factors For Steel-concrete Composite Beam Bridge

In recent years,with rapid development of China’s economy,driving speed and weight of vehicles continued to increase.Thus,the coupling vibration of vehicle-bridge have become much more prominent.In order to ensure the safety,applicability and durability of bridges,the safety and stability of vehicles,it is necessary to conduct in-depth research on vehicle-bridge coupling vibrationAt present,there is a lack of research on vehicle-bridge coupling vibration of composite beam bridges and its influencing factors.In this paper,the steel-concrete composite beam bridge was taken as the research object.Based on the partial-interaction Timoshenko composite beam theory,the dynamic interaction between the vehicle and the structure was studied.The main research contents,research methods and research results of this paper are as followed.(1)For vehicle-bridge coupling vibration of composite beam bridges,the vehicle and the bridge were simplified as a spring-damping-mass system and a partial-interaction composite beam based on Timoshenko beam theory.The coupled governing equations of the vehicle-bridge coupling vibration were derived,and the natural frequencies and free vibration modes were calculated by state space method.Furthermore,the forced vibrations of bridges were solved by mode superposition method.Using parameters of the composite-beam model in the existing literature,the first 10 natural frequencies and modes of a simply supported beam were obtained by the related MATLAB program.Through comparison with the results in the existing literature,the feasibility and practicability of the proposed method were verified.(2)Based on a composite beam bridge,the proposed vehicle-bridge coupled vibration response analysis program was adopted to analyze the vehicle-bridge dynamic interaction of steel-concrete composite beam bridge under the moving vehicle loads.The results show that the theoretical results of this paper were in good agreement with the analysis results of Yang et al.As a result,it can be seen that when the offset frequency of the basic frequency of the beam approaches the fundamental frequency of the vehicle,the resonant response will occurred.(3)Taking a simply supported steel-concrete composite beam bridge as an example,numerical calculations were carried out by using the developed program to analyze the vehicle-bridge coupled vibration response with the different speed of the vehicle,the weight of the vehicle,the surface roughness of the bridge and the stiffness of the shear connector.How these four factors influence the coupled vibrations were analyzed and summarized.The results show that the speed of vehicle,the weight of the vehicle,the surface roughness and the stiffness of the shear connector have a salient effect on vehicle-bridge coupled vibration.The research results of this paper can serve as basic references for vehicle-bridge coupled vibration and the vibration-based structural damage detection of composite beam bridges.Meanwhile,it also has important theoretical and practical significance for the design,construction and daily operation and maintenance of composite structural bridges.