Analysis Of Shear Lag Effect Of Steel Box Girder On Light Composite Deck Of Self-anchored Suspension Bridge

Self-anchored suspension Bridges are highly competitive in modern urban bridge construction due to their advantages such as no need of ingot structure,the main cable can be directly anchored to the beam end and flexible structure selection.The light composite bridge deck is the orthotropic steel bridge faceplate--STC concrete layer,which is a composite bridge deck system in which the STC concrete pavement layer is poured on the orthotropic steel bridge faceplate,and the common force is realized as a whole through the connection of shear nails and steel mesh.Its characteristics are that it can better solve the risk of fatigue cracking of steel bridge panel and the problem of bridge deck pavement being vulnerable to damage.However,the shear lag effect of the girder under the action of the sling force is very obvious in the actual engineering.If the non-uniformity of the longitudinal normal stress in the transverse direction of the bridge panel is not considered,it is not consistent with the actual force,which may lead to the failure of the steel bridge panel due to the excessive local force.Therefore,based on the engineering background of zhaohua-xiangjiang bridge,this paper conducts a comprehensive research and analysis on the shear lag effect of steel box girder on the light-weight composite deck of self-anchored suspension bridge through theoretical derivation and finite element software analysis.The main work includes the following aspects:1.Based on the variational principle of energy,different buckling functions are assumed to simulate the longitudinal displacements of different fins,and according to the principle of minimum potential energy,the governing differential equation and the closed solution of the longitudinal normal stress of steel box girder of light composite bridge deck are derived.2.Based on the engineering background of zhaohuaxiangjiang bridge,the finite element model of the whole bridge and the local finite element model are established by using Midas Civil and ANSYS finite element software respectively,and the influence of the sectional length of the local finite element model on the accuracy of normal stress is studied,which provides reference value for the research on the main girder of the suspension bridge with the bridge panel as the light composite deck.3.By local finite element model,key section of light composite bridge steel box girder at construction stage of the shear lag effect of different sling tensioning stage research,studies the key section in the sling tensioning stage each moment the change of the axial force ratio,and the key section of roof and floor in the tension distribution regularity of shear lag phase,it is concluded that the key section of the shear lag effect is the most serious tensioning stage.4.By using the local finite element model,the shear lag effect of key sections of steel box girder of light composite bridge deck under constant load during the bridge formation stage is studied,and the distribution law and difference of shear lag effect in sections with and without sling anchorage are studied.5.Through the local finite element model,the influence of the overall temperature rise(fall)on the shear lag effect of each key section of steel box girder of light composite bridge deck is studied.By co MParing the finite element calculation results of the normal stress of each key section under the pavement of STC concrete layer and traditional asphalt layer,the influence degree of STC concrete layer on the normal stress of each key section is studied.The effect of cross slope on the shear lag of each key section of steel box girder is studied.