Study On Stability Bearing Capacity Of The I-beams Steel Girder Double Cantilever Girder Bridge

Double cantilever beam bridge structure is simple, and the additional stress could not cause abutment uneven subsidence, so it have become a kind of suitable for the bridge built on soft soil foundation. Currently, the research of the overall stability of simply supported beam and cantilever beam has been basically mature, However, due to exist on both ends of the cantilever, The boundary conditions and mechanical characteristics of the double cantilever beam more complicated than the simply supported beam and cantilever beam. But so far, the study of double cantilever beam bending torsional buckling and rarely, and the related literature and foreign standard of no put forward clear and reliable calculation expressions of bearing capacity of flexural member overall stability, so the article is research the overall stability of steel girder double cantilever girder bridge.Based on Raykeigh-Ritz energy method analysis of the simplified into the overall stability of the double cantilever beam, derived the double cantilever beam under transverse load overall stable approximate calculation formula of the critical moment. And the simplified calculation formula of calculation results are compared with those of the finite element analysis results, the calculated results are in good agreement, but the theoretical value smaller,is safe for structure. At the same time, by using the finite element method to curved beam overall stability critical bending parameter analysis. Selection of parameters for different load form, the torsional rigidity coefficient, simply supported across span and load point position,height of cross section, the overhanging ratio; Analysis of various parameters on the buckling of beam bending and twisting are calculated respectively.Using multiple linear regression analysis of SPSS data analysis software, put forward the double cantilever beam under uniform load and concentrated load critical moment formula of design Suggestions according to the load form, overhanging length, and the height of the load point is different, the design recommended formula of concrete parameters is also different.Also refer to specification for design of steel structures in the beam of the overall stability coefficient calculation expression, combined with the regression analysis results, the proposed double cantilever bending beam method for calculating the elastic buckling critical bending moment.