Mechanical Analysis Of Single-span Skewed Bridges With Considering Shear Deformation Effect

The medium and small bridges of highway and railway line.Often using the design approach of obey direction of the line,Take the bridge of central axis and resistance line?water direction oblique crossing design into a skew girder bridge. With the rapid development of our country's transport business,the application of medium and small span skew girder bridge structure is more and more widely,domestic and foreign scholars have carried out extensive and in-depth research,the static characteristic research of the internal force and deformation is systematically.but most of the theoretical basis of previous research as Euler beam theory,think the effect of shear on the internal force and deformation of the less affected,and thus be ignored.how is influence laws of shear effect on the internal forces and deformation of the skew bridge and how is analyzed with mechanics, The current research work is not very deep,Worth further discussing.so this paper is based on force method and diagram multiplication of Timoshenko deep beam theory,do the following work:(1)a calculating method with considering the influence of shearing deformation was established for single span static skewed beam. The deformation formula of single span staic skewed deep beam under common load were also deduced. Through the parameter of skew angle ?planar configuration and bending shear stiffness ratio change,Analysis the skewed bridge of Single box single room without cantilever influence laws of shear effect on the internal forces.(2)a calculating method with considering the influence of shearing deformation was established for single span statically indeterminate skewed beam. The reaction force ?internal force and deformation formula of single span statically indeterminate skewed deep beam under common load were also deduced. Through the parameter analyses of span, skew angle and planar configuration of standard A-type single-span box girder, it abtains to some summaries that: the smaller the span is and the greater the skew angle is, the greater the influence of shear deformation effects on the deflection of skewed beam bridges. But its influence on internal forces, deflecting slope and twist angle are so small to be neglected.(3)In view of the engineering four familiar special skewed beam(simply supported rectanguler beam?parallelogram oblique beam ?right-angle trapezoidal oblique beam?isosceles trapezoid oblique beam).analyze the shear deformation influence on the calculation of the internal force and deformation; The deflection calculations for skewed bridges with medium and small spans should adopt Timoshenko deep beam theory with considering shear deformation effect, otherwise it would underestimate the deflection results.(4)establish a calculation method with considering the influence of shearing deformation and bearing stiffness of the single span skewed beam internal forces. These derived formulas were verified by finite element method. It is concluded that the shear deformation and bearing stiffness on the calculation of internal forces of the single span skew girder bridge is small; The calculating formulas derived in this paper are convenient to design staff, and can promote the development and evolution of skewed girder bridge, enrich the calculating methods for skewed girder bridge.