Finite Element Analysis Of Static Performance Of Curved Continuous Double-box Composite Girder Bridge

The curve steel-concrete combination box beam bridge not only has a high bearing capacity and torsional stiffness,but also has good overall stability and spanning capacity.However,due to the coupling effect of curved beam bending and torsion,the stress of curved composite box girder bridge in operation period is very complicated.This paper takes curved continuous composite box girder bridge as the research object,and the finite element software ABAQUS was used to analyze the mechanical properties of curved continuous composite box girder bridge.(1)Through the review of relevant literature at home and abroad,the inadequacies of existing research are summarized,and the stress characteristics and analysis and calculation theory of the curve beam bridge are described in detail,and the deformation differential equation of curved beam is derived.And perform refined modeling analysis of the continuous combination of the curve.By establishing the spring unit to simulate the shear connection between steel beam and bridge panel.The curve combination box girder model is modified according to the existing test data to ensure the accuracy and reliability of the finite element calculation results.(2)The influence of relevant structural parameters on the mechanical performance and deformation state of curved composite box girder under load was studied,including the influence of ultra-high transverse slope of circular curve,the number of middle diaphragm,the high-span ratio,the thickness of steel beam bottom plate and the radius of the curve,and obtains the change law of internal force,deformation and torsion angle of curved composite box girder caused by the change of structural parameters.Through comparative analysis,it is found that the setting of the middle diaphragm can obviously increase the torsional stiffness of the curved composite box girder and improve the integrity of the inner and outer box girder.The increase of the transverse slope of the curved beam increases the longitudinal stress and vertical displacement of the bottom plate of the steel beam in and out of the mid-span section to a certain extent,and aggravates the torsion effect of the section.Increasing the high-span ratio,floor thickness and curve radius can improve the longitudinal stress,vertical displacement and torsion of steel beam floor to different degrees,but increasing the floor thickness has no obvious improvement effect on the mechanical performance.(3)A case model of curved continuous composite box girder bridge is established,the internal force distribution and deformation of curved continuous composite box girder under the load of standard lane are calculated and analyzed,and the antioverturning stability of the structure under eccentric load condition of heavy vehicles is checked.The results show that compared with single lane loading,the vertical displacement and the longitudinal tensile and compressive stress inside the steel beam produced by two-lane loading are larger.Compared with the inner lane loading,the outer lane loading results in greater tensile stress and vertical displacement.The torsional effect is the most obvious when the outer lane is loaded,and it is the most adverse to the anti-overturning stability of the structure,among which the support located inside the beam end is relatively more prone to separation.Finally,optimization measures and methods for improving structural mechanical properties and antioverturning stability of curved continuous composite beam bridges are presented,which can provide reference for future engineering design and construction.