Study On The Spatial Mechanical Properties Of Curved Composite Box Girders With Corrugated Steel Webs

As a new type of structure,the composite box girder bridge with corrugated steel webs accelerates development of this type of bridge in the field of road traffic,due to many advantages around these bridge.The composite box girder bridge with corrugated steel webs are gradually applied to curved bridges,in order to meet the needs of urban development and road planning.While,because the curved composite box girder bridge with corrugated steel webs has complex forms of stress,unclear force-transferring mechanism,a set of research on comprehensive structural mechanical properties of the curved composite box girder bridge with corrugated steel webs are lack.The main contents are as follows :(1)Using the energy method,the mechanical properties of curved composite box girder bridge with corrugated steel webs under the combined action of bending,shear and torsion are studied.Based on the principle of minimum potential energy,the elastic differential equation of simply supported curved composite box girder bridge with corrugated steel webs is derived,when the strain and external potential force energy are considered which are generated by bending,torsion,distortion and shear deformation of the bridge.The equations have been solved using the Galerkin method,the torsion angle,the vertical deflection and the normal stress of the curved composite box girder bridge with corrugated steel webs are obtained.(2)Adopting rod structural mechanics theory and finite element analysis method analyze the internal force,the vertical deflection,the lateral displacement,the torsion angle,the bearing reaction force and the cross-sectional stress of the curved composite box girder bridge with corrugated steel webs.Then,obtained the trend of various mechanical indexes with the changes of curvature radius of the bridge.Upon the premise of ensuring the calculation error,put forward the limit value of substitute the curve using straight bridge.(3)According to the analysis on the section stress of the curved composite box girder bridge with corrugated steel webs,the section stress are divided into bending stress,torsional warping stress and distorted warping stress by the structural stress characteristics.Based on current research results,the stress resolution method of curved composite box girder bridge with corrugated steel webs is proposed,so that the section stress of the curved composite box girder bridge with corrugated steel webs can be easily decomposed into positive symmetric stress and antisymmetric stress,namely bending stress and warping stress.The results of the stress resolution method are verified via energy method and straight beam method.Applying this method,the corresponding stress of the curved girders structure can be calculated indirectly through the stress of the straight girders,achieving that the effect of using straight girders stress to calculate curved girders stress.(4)Clearly definition of the shear lag effect of the curved composite box girder bridge with corrugated steel webs.The shear lag coefficient of the curved composite box girder section is calculated by using the straight beam method and decomposed stress method proposed in this paper.To satisfy the effect of solving the distribution of shear lag coefficients of curved beams by straight beams,the calculation results of the two methods must reach well accuracy.Analysing the width height ratio,the wide span ratio,the hanging wing ratio,the radius of curvature,the thickness of roof and floor,the thickness of the steel web plate,and the load distribution function form affect the shear lag coefficient of simply supported curved composite box girder bridge with corrugated steel webs.It is clear that various structural parameters arose different regularity on shear lag coefficient.(5)The warping stress of the curved composite box girder bridge with corrugated steel webs under the action of anti-symmetric concentrated load and uniform load are analyzed,the stress distribution characteristics of each section of the box girder are defined,and the warping stress of the bridge is obtained by means of the stress decomposition method,which is compared with that of the straight girder method to prove the feasibility of the method.Further,getting on parametric analysis of box girder to prove the universality on stress decomposition method which is proposed in this paper.