Material Constitutive Model Research Of Analysis On Shear Lag For Pre-stressed Concrete Curved Box-girder Under The Action Of Vehicle Load

Currently,the box girder has been widely used in city viaduct,rail transportation and interchanges.In the design of curved box girder bridge,shear lag effect aroused high attention,there are a large number of scholars have studied and achieved a lot.However,study about shear lag effect on curved box girder under the relevant traffic loads is also very little.Based on previous studies,the finite element was usd to study the shear lag effect on prestressed concrete curved box girder under vehicle load,especially the influence of different concrete material constitutive model for shear lag effect of curved box girder.(1)The paper introduces the concept of non-linear,focusing on the material nonlinear problems when analysing curved box girder.Three constitutive models of concrete and one constitutive model of rebar are selected by means of generalization and summarization.Make a combination of three constitutive models of concrete and one constitutive model of rebar respectively to analyse the shear lag effect of curved box girder.(2)By ansys finite element software to establish a finite element model of prestressed concrete simply-supported curved box girder.Through the study of finite element model and analyse the effects that such parameters as the vehicle load size,load acting position,vehicle velocity have on shear lag effect under the action of vehicle load.Besides,we also analysed the lengthwise shear lag effect of simplysupported curved box girder and obtained the most unfavorable cross section of the box girder under the action of vehicle and some rules about the shear lag effect of simply-supported curved box-girder as well as the optimal concrete constitutive model of analysing these problems.(3)In considering three different concrete constitutive model working conditions,shear lag effect of the curved box girder analyzed following conclusions:the most unfavorable section of the box girder was cross section in the process of dynamic vehicular loads;it was not obvious within a certain range of the value of the changing load for the box girder changed;vehicle load position has some influence on Shear lag;Speed of vehicle load influences a lot on the effect of shear lag for box girder,which appeared that phenomenon of the box girder shear lag becomes more evident with the increasing speed;different constitutive model for the shear lagcoefficient curve has the certain differences and the optimal concrete constitutive model was the Hognestad model by comparison with the experimental results,which was advised to preferentially adopted in the analysis of such problems.