Study On Dynamical Behavior And Vibration Of Concrete-filled Steel Tube Skeleton Arch Bridge

With the rapid development of China’s infrastructure industry,the construction of highway and railway bridges has also developed rapidly.And steel pipe concrete strength frame arch bridge because of its beautiful grand,high bearing capacity,big span,the advantages of convenient construction,good economic benefit,is widely used in highway,railway bridge construction.In recent years,the rigid frame bridge of steel tube has been developing towards the light direction,and its self-weight is getting smaller and smaller,and its dynamic response under the action of dynamic load is becoming more and more important.In this paper,the dynamic characteristics and dynamic response of a concrete filled steel tube reinforced concrete arch bridge(glass ditch bridge)for 170 m highway are analyzed with the help of the finite element software Midas Civil.The main work contents and conclusions are as follows:1.This paper briefly introduces the development of the stiffening skeleton of the concrete filled steel tube arch bridge,and the research status and significance of the dynamic characteristics and dynamic response of the steel tube concrete stiffened skeleton arch bridge.2.The full bridge space finite element model of the glass ditch bridge is established and its natural vibration characteristics are analyzed.Then,some structural parameters(steel pipe wall thickness,steel pipe outer diameter,core concrete projectile,outsourced concrete projectile and so on)are changed and the dynamic characteristics of the bridge are calculated and analyzed.From the analysis results,the long-span concrete filled steel tubular rigid frame arch bridge is a more flexible structure with a lower self vibration frequency,and the change of the structural parameters,such as the thickness of the steel tube,the outer diameter of the steel tube and the core concrete,has little influence on the self vibration characteristics of the whole bridge.3.By using the two different seismic response analysis methods(response spectrum method and dynamic time history analysis method)provided by MIDAS/Civil,the dynamic response of the glass gully bridge under the earthquake action is analyzed,and the analysis results of two methods are compared.The results show that the analysis results of the response spectrum method are mostly unsafe.The dynamic time history analysis and the response spectrum method should be used to analyze the seismic response of the long-span concrete filled steel tubular arch bridge with complex dynamic response.At this time,the response spectrum method can be used as an estimate or check method.4.With the help of dynamic time history analysis provided by MIDAS/Civil,the dynamic response of the glass gully bridge when the vehicle passes through the bridge structure at different speeds and different distances is analyzed.Then the time history of the dynamic response of the glass ditch bridge under the impact load is studied.The results show that the vibration of the glass gully bridge caused by vehicle load is smaller,the smaller the distance the vehicle distance is,the greater the impact magnification of the vehicle load on the displacement and internal force of the bridge,and the impact effect is very obvious under the impact load,providing some basis for the operation and management of the glass ditch bridge.