Theoretical Analysis And Experimental Study On Shear Lag Effect Of The New Composite Box-Girder With Corrugated Steel Webs

The low flanges(RC slabs)of traditional composite box girder with corrugated steel webs are replaced by the flat steel plates in new-type composite box girder.Because of its light weight,convenient construction and good mechanical properties,new-type composite box girder provides a new option for the bridge design in China.But now the study on mechanical properties of new-type composite box girders with corrugated steel webs is still deficient,It affects the application and popularization of this kind of structure.Therefore,the study of the mechanical properties of new composite box girder has more theoretical and practical value.The main contents of this paper are as follows:1.In consideration of the accordion effect,shear lag,shear deformation and other factors,the energy variation principle is applied to establish the governing differential equations and corresponding natural boundary conditions.2.The differential equations are solved,and the closed solution of the generalized displacement is obtained,and then the fine analysis of the spatial mechanical behavior of the new-type composite box girders is completed.3.Meanwhile,the 3D finite element(FE)model of box girders is built to simulate the spatial mechanical characteristics under different working conditions,thus the mechanical performance of new-type composite box girders is studied by Finite Element Method,the validity of the theoretical method is verified by comparing the finite element numerical solution with the analytical solution in this paper.4.Compared with the mechanical properties of composite box girder with flat steel webs with same thickness,the study on the crinkled effect of new composite box girders is completed,the influence of different boundary conditions are analyzed.5.The test models are prefabricated,the sensors are arranged,and the test of the model bridge are carried out.Based on these,the validity of the theoretical analysis and the calculation precision of the finite element simulation are verified.6.Based on the test test and the finite element simulation,the theoretical analysis method is modified and perfected.This paper presents a fine analysis method for the vertical bending behavior of new-type composite box girders,which has a certain reference value for improving the theoretical analysis and design of such structures.