The Study Of Shear Lag Effect To Speed RailwayVariable Cross-section Continuous Box Girder Bridge

Along with China's economic developing,traffic construction also changed with each passing day.Bridge engineering,which is closely related to us,is toward the direction of diversification.Because the box beam has good structural characteristics and mechanical properties,box girder cross section is widely used in bridge engineering.Due to the wide box girder with transverse the flange,the distance between web and thin wall,etc,So the wing plate under load is uneven shear deformation.Cross section normal stress distribution along the cross section is no longer a straight line,but a curve.This is the shear lag phenomenon.Ignore the effect of shear lag effect will lead to corresponding transverse cracks which appear,and lead to unsafe of structural design.Serious that may cause the destruction of the bridge structure.For the shear lag effect a lot of research has been done,but most of the studies are focused on simple bridge,such as the cross section of box girder,and the load on bridge are focused on the static load or weight.but in the course of the bridge's life,Bridge structure basically is under dynamic load,therefore the analysis of shear lag effect only from static is not enough.In this paper,taking variable cross-section continuous box girder bridge as the research object,which is commonly used in bridge engineering,taking the numerical analysis method,using ansysinfinite element analysis software.Respectively from the dynamic and static loads,analyzed the shear lag effect of control section.The main research work includes:(1)Make a model of high speed railway variable cross-section continuous box girder bridge,completed a variety of possible load forced on the bridge and calculation of finiteelement model(2)Study the stress of vertical distribution and horizontal distribution,as well as the distribution of the shear lag effect of the structure of the train under static load.(3)Analyze the action of the stress time history and the shear lag coefficient of the structure of the train under dynamic load,summarize the unfavorable situation of structure under dynamic loading.(4)Analyze the influence of the different speed of high speed railway train to the shear lag effect of variable cross-section box girder bridge.(5)Compare the structural internal force under the dynamic and static load,and find out the relationship between them.