Creep And Shear Lag Effect Analysis Of Steel-concrete Composite Box Girder

Corrugated steel web composite box girder is a new type of steel-concrete composite structure,which gives full play to the advantages of steel and concrete materials.It has remarkable economic and technical benefits and social benefits.Because the creep effect of concrete material increases over time,but steel does not,the force between the two will change with time.Because of the effect of box girder shear lag.The stress redistribution of section caused by creep will also changed by shear lag.Therefore,it is necessary to consider the influence of creep on shear lag effect of box girder and to establish a corresponding theoretical analysis method.Steel web composite simply supported box.In this paper,the influence of creep effect on shear lag effect of two kinds of bridges is theoretically analyzed and verified by numerical simulation.The main points are as follows:(1)Using energy variational method,the shear lag control differential equation of simply supported box girder with corrugated steel webs considering creep effect is established,and the stress formula of box girder considering creep effect under concentrated force and uniform force is derived.The influence of creep effect on shear lag effect is analyzed theoretically.(2)The finite element model of simply supported box girder with corrugated steel web is established by ANSYS.Box girder under concentrated force the creep(creep time of 1500 days),the finite element numerical solution and theoretical analysis.(3)For the existence of system conversion simply-supported continuous continuous box girder with corrugated steel webs,deduces the additional bending moment shear lag effect and the stress formula,according to the T-B equation(equation by effective modulus method and the age adjusted),stress formula is deduced considering creep and shear lag effect.The variation stress of mid span section and fulcrum section of corrugated steel web combined continuous box girder is analyzed when creep time is 0~1500 days.(4)According to the specification on coagulation.In order to calculate the creep effect of corrugated steel web composite box girder,a finite element model of corrugated steel web composite box girder and continuous.Box girder is established by using the second development tool of ANSYS,the user subprogram usercr.F is modified to calculate the creep effect of the corrugated steel web composite box girder.The effects of creep and shear lag effect on the stress of composite box girder are calculated respectively.(5)The shear deformation and shear force are considered simultaneously under concentrated load and uniform load of simply supported box girder with corrugated steel web by energy variational method.The calculation formula of deflection of hysteresis effect.The elementary beam theory of composite box girder with corrugated steel webs is calculated.Shear deflection and shear lag deflection.The deflection composition of the composite box girder with corrugated steel webs and the long-term time-varying deflection of the box girder considering creep effect are analyzed.