Buckling Behavior Of Curved Box Girder With Corrugated Steel Webs

Box girder bridge with corrugated steel webs is a kind of bridge form with great development potential,which has been widely concerned by the industry due to its light weight and high prestress efficiency.Since its appearance,the buckling stability of webs has been a hot issue in research.The research on straight bridges with corrugated steel webs of constant and variable cross-sections is more in-depth at home and abroad.Due to the fact that the curved corrugated steel web slab bridge is still in the exploratory stage,most of the existing projects are built in Japan,and have not been popularized in China,there are still many deficiencies in the study of its web stability.Based on the existing theories,the shear buckling behavior of box girder with curved corrugated steel webs is studied as follows:The local buckling of curved wave plate is equivalent to that of rectangular single plate,and the local buckling formula of curved wave web is derived by using the principle of minimum potential energy.Inspired by the mechanics of thin shells,the curved wave plate is abstracted as an orthotropic open shell,and the formula of the global buckling strength of the curved wave plate is derived by using the energy method.Because the local buckling of curved wave plate and straight wave plate is almost the same,both of them occur in the buckling of rectangular single plate,so there is no difference in the formula of local buckling between them.The difference is that the change of constraint conditions leads to the change of buckling coefficient.When the radius of the curve is large,the term is close to zero,so it can be calculated as a straight bridge.A lot of finite element analysis is carried out.Before the analysis,the relationship between the curvature radius of curved corrugated steel web beam and the difference of internal and external wave angles of wave plate is discussed in detail.The research object is transformed from radius and center angle to the difference of internal and external wave angles and beam length.The research efficiency is improved.The structural parameters of the built curved wave plate box girder bridges are sorted out.According to the actual bridge parameters,a large number of curved wave plate box girder models are established.Through calculation,the influence of the internal and external bending angle difference and beam length on the local buckling strength of curved wave plate box girder is obtained.By comparing the results of modeling and formula calculation,the boundary conditions of local buckling sub plate of curved wave plate box girder are studied,and the local buckling correction formula of curved wave plate box girder is given.The same idea is also applied to the overall buckling of curved wave plate.According to the actual bridge parameters,a series of models of curved wave plate box girder with overall buckling are established,and the influence of internal and external bending angle difference and beam length on the overall buckling strength of curved wave plate box girder is discussed,which is confirmed by the derived formula of overall buckling strength of curved wave plate.Then,the boundary conditions of the integral buckling of the curved wave plate box girder are studied by comparing the calculated value of the finite element method with the calculated value of the formula,and the modified formula of the integral buckling of the curved wave plate box girder is given.Through the finite element analysis of the height,width,bending angle and thickness of the curved wave plate,as well as the section size of the box girder,the change law of the buckling mode and load eigenvalue of the curved wave plate is studied.