The Bending And Torsion Behavior Of Composite Curved Box Grider Bridge With Corrugated Steel Webs

Composite box girder with corrugated steel webs is a new type of structure,which has the advantages of light weight and non-cracking of webs.It has been widely valued worldwide and widely used in practical engineering.Many scholars have conducted a lot of research on the mechanical properties of corrugated steel webs combined with linear box girder.However,due to the complex mechanical behavior of composite curved box girder with corrugated steel webs,the theoretical research is relatively difficult,and the theoretical and experimental research is insufficient.This paper mainly study the bending and torsion behavior of composite curved box girder with corrugated steel webs.The main work are as follows :1.The existing bending theory of composite linear box girder with corrugated steel webs is summarized and divided into five categories.The first two theories are based on the assumption of quasi-planar section,and the latter three theories meet that each plate is still a plane section after longitudinal deformation.In this paper,the second and fifth bending theories are studied in detail,and the establishment process is deduced.Through comparative study,it is found that the axial force,bending moment of concrete roof and floor and shear force of steel web calculated by two kinds of bending theory are equal.The second type of theory with fewer parameters is selected to study the bending behavior of composite curved box girder with corrugated steel webs.2.Based on the classical restrained torsion theory of thin-walled box girder,the restrained torsion theory of composite linear box girder with corrugated steel webs is divided into five categories,and the first and fourth restrained torsion theories are studied in detail.Through comparative study,it is found that the two kinds of constraint torsion theory are based on the second theory of Umanskii,and the governing differential equations of the two kinds of constraint torsion theory are the same.The first kind of restrained torsion theory is selected to study the restrained torsion behavior of composite curved box girder with corrugated steel webs.3.Based on the bending theory and constraint torsion theory of composite linear box girder with corrugated steel webs,the bending and torsion calculation method of composite curved box girder with corrugated steel webs is established by generalized coordinate method.The governing differential equation and boundary conditions are established by principle of virtual work.The influence of initial curvature is considered in the derivation process.The finite beam model is established by element stiffness matrix and load array,and the calculation program is compiled by FORTRAN language.Through the program calculation,the finite beam segment model results are basically consistent with the three-dimensional simulation model results,and the finite beam segment model meets the design accuracy and safety requirements of practical engineering.4.The finite element method is used to study the lateral distribution of displacement and stress of composite curved box girder with corrugated steel webs under different curvature radius,and the variation law of displacement and stress of composite curved box girder with corrugated steel webs with curvature radius are obtained.Research shows that with the increase of curvature radius,the displacement and stress of curved box girder are gradually close to those of linear box girder,and the mechanical behavior of curved box girder with corrugated steel webs is close to that of linear box girder.