Evaluation On Vibration Characteristics Of An Arch Bridge Before And After Reformation Based On Vehicle-Bridge Coupled Vibration Analysis

With the rapid development of our country’s transportation facility,the bridge construction has also been continuing to expand.Concrete-filled steel tubu arch bridges have become more and more favorite by designers,and have been used in actual projects.As the number of vehicles on the bridge increases,there are more and more problems caused by the impact of vehicle loads on the bridge.Large vibrations will be generated when the vehicle is running through,which will seriously affect the structural safety and driving comfort.The coupling effect between the vehicle and the bridge is important for such problems,therefor scholars pay more and more attention on it.In this paper,an arch bridge before and after reinforcement is taken as the research object.A series of diseases existing after the completion of the bridge and the vibration problems caused by vehicle loads are introduced and analyzed in detail,and three kinds of reinforcement schemes are given for these problems,mainly including the following contents:(1)Summarizing the development status of concrete-filled steel tubu arch bridges and the current research status of vehicle-bridge coupled vibration theory in China and abroad,and introduce the research background,main research contents and significance of this research.(2)The finite element analysis method is used to establish the bridge model,and two kinds of vehicle models with 2 degrees of freedom and 12 degrees of freedom are idealized as mass-sprung vibration system,and the vehicle-bridge coupled equation is established.Using FORTRAN language,a numerical simulation program for vehicle-bridge coupled vibration analysis is created.The main calculation principles and calculation methods of the method are introduced,and the correctness of the program is verified by comparison with other documents.(3)Analyzing the eigenvalue of the main structure of the bridge using the finite element analysis software Midas civil,and calculating the vibration modes and natural frequencies of the main structure part.Discussing arch rib simplification,bridge deck modeling methods and the influence of the arch bottom connection methods and other factors on the natural vibration characteristics.(4)Using self-created program to conduct vehicle-bridge coupled vibration analysis,and analyzing the dynamic response and vibration characteristics of the concrete filled steel tube arch bridge considering the effects of bridge stiffness,road surface irregularity,driving speed and vehicle weight,etc.,and evaluating the vibration characteristics of the bridge before and after reinforcement as well as the vibration characteristics of the bridge before and after reinforcement and the running comfort and safety of vehicle.