Analysis Of Mechanical Properties And Parameters Of Variable Cross-section Wide Box Double-chamber Corrugated Steel Web Girder Bridge

With the increasing traffic volume,the wide box multi-chamber corrugated steel web composite box girder bridge is more and more favored by designers because of its unique stress performance.Based on the project of Zhanhe Bridge on Shenma Road in Pingdingshan City,this paper first uses the finite element software Ansys to establish a fine spatial finite element model;then this paper analyzes the mechanical properties of the variable cross-section wide box double-chamber corrugated steel web composite box girder bridge;finally,this paper discusses the variation of the mechanical properties of the variable cross-section wide box double-chamber corrugated steel web composite box girder bridge with the width of the bridge cantilever plate,box girder width,web inclination angle,diaphragm spacing,and liner concrete style.The main work completed and research results obtained in this paper are as follows:(1)This paper verifies the applicability of the existing research results to the wide box double-box corrugated steel web composite box girder bridge with variable cross-section,including: the flange plate bending normal strain meets the "quasi-flat section assumption";the flange plate bears about 99% of the bending moment;the web bears about 85% of the shearing force;the lining concrete bears about 70% of the total shearing force.(2)The shear lag effect at the side fulcrum and middle fulcrum is significant.Among them,the shear lag effect of the cantilever plate at the side fulcrum is more prominent than that in the box top plate,and the shear lag effect at the middle fulcrum is more prominent than the cantilever plate.The torsion angle and stress increase coefficient of the side span are both small,and the torsion angle of the mid-span mid-section is the largest.(3)The greater the width of the cantilever plate,the greater the bending rigidity of the box beam.The greater the width of the box girder,the greater the bending stiffness of the box girder.The box girder deflection is minimum when the web inclination is 90 °.The change of the distance between the lined concrete and the diaphragm has little effect on the bending stiffness of the box beam.(4)The shear lag coefficients of side and mid-span bridge decks increase with the width of the cantilever plate,and the change of the cantilever plate width has little effect on the shear lag effect of the bottom plate.The shear lag coefficient of the bridge deck increases with the width of the box girder,and the shear lag coefficients of the bottom and mid-span floors increase with the width of the box girder.The shear lag effect of bridge deck and floor is obvious with the increase of web inclination.As the spacing of the diaphragms decreases,the shear lag effect is somewhat reduced,but the overall effect is small.Lining concrete can reduce the effect of shear lag at the midpoint.(5)The change of the cantilever plate width has little effect on the torsional performance of the box beam.The larger the width of the box girder,the less the effect of the eccentric load on the structure.The torsion performance is best when the web inclination is 95 °,and the effect of eccentric load on the structure is the smallest.The smaller the distance between the diaphragms,the greater the torsional rigidity of the box girder,and the less the effect of the eccentric load on the structure.Lining concrete has little effect on the torsional performance of the structure.(6)In this paper,the empirical formulas for the geometric parameters of the deflection,shear lag coefficient,torsion angle,and stress increase coefficient varying with the wide-section double-box corrugated steel web composite box beam with variable cross-section are given for engineering design reference.(7)This paper presents a new lined concrete style——lattice lined concrete,which is convenient for construction and can play the role of conventional lined concrete.The shared shear force is between 70% and 75%.