Study On Distortion And Transverse Internal Force Of Steel And Concrete Composite Box Girder

With the development of modern science,the structure form tends to diversification,the composite box girder of steel and concrete gradually goes into people's vision.This girder makes full use of the good performance of the steel and concrete.It has the advantages of light weight,small size of section,the construction is convenient and so on.At present,the theory which mostly used in the elementary beam is adopted on box girder,the research on distortion and internal force of the composite box beam are little at home and abroad.In this paper,the distortion and internal force of the composite box beam of straight line and curve which is based on the energy variational principle and elastic mechanics method is studied.Based on the energy variational principle and the principle of minimum potential energy,taking the distortion angle as the basic unknown parameter,the distortion of composite box beam differential equation is built,by using the elastic foundation beam analogy method to solve this equation,the formulas can obtain the distortion angle and distortion moment.By using the elastic plate theory,the distortion differential equation is established about the same distortion angle as variables considering the shear deformation.This two forms are compared with each other,the accuracy of the formula is confirmed with each other.In addition,linear combination beam about the transverse internal force is established under the distortion load.Under the influence of eccentric load,the distortion angle and the distortion torques are the maximum in the position of the cross.Gradually reduce to both ends.The distortion effect of the 1/3 beam is obvious in the midspan.The distortion angle and the distortion torques are almost zero at the end of the beam,and the deformation can be neglected.Based on the energy variational principle and the principle of minimum potential energy,taking the distortion angle as the basic unknown parameter,the distortion of composite curve box beam differential equation is built.Due to equation is complicated,the equation is solved by stiffness method that can obtain computation about distortion angle,distortion moment,distortion stress and about other parameters.On the basis of application of finite element software ABAQUS,the calculation model of curved composite box girder is established,changes of distortion angle and transverse internal force deformation analysis under the the eccentric line load.On the basis of models,change the parameters,analysis of different high span ratio,aspect ratio,the thickness of steel plate and concrete roof,floor thickness,load amplitude,angle and other parameters on the distortion angle and lateral force,and gives the conclusion that can be used for design.The distortion angle of the curved composite beam is not obvious under the condition of the high ratio of the curve.When the span depth ratio is different,the height of steel web increases when the distortion occurs.The distortion angle and the lateral displacement decreases,which is use for the structure itself to resist the distortion.In the case of fixed curvature radius,the larger the aspect ratio,the larger the lateral displacement value,it means the wide box beam is disadvantage to resist distortion.Under the same curvature radius,the larger the angle,the larger the distortion angle and the lateral displacement,it means that the trapezoidal box beam is better than the rectangular box beam to resist distortion.