Deflection Calculation of New Type Composite Box Girder with Corrugated Steel Webs Based on Reddy Theory

In order to accurately calculate the deflection of a new type of composite box girder with corrugated steel webs (CSWs), Reddy high-order theory is used to analyze the slip deformation of the steel-concrete interface and the high-order shear deformation effect of the whole section; the isoparametric finite element determinant of the new-pattern composite box girder with CSWs is derived by the principle of minimum potential energy, using the shape function as the interpolation function of height variation in the element. Taking an 8.0 m long new-pattern simply supported composite box girder with CSWs as an example, the corresponding calculation program is compiled by the proposed methodology and applied to calculate vertical deflections of the beam under concentrated and uniform load. Results of the finite element simulation are then compared with those of model tests to verify the reliability of the analytical calculation method. Finally, influences of the shear stiffness of shear key, type of corrugated web, height ratio of sub-beams, and height-span ratio on the deflection of the new type of composite box girder with CSWs are analyzed. The results show that after taking into consideration the full-section shear deformation effect of the new type of composite box girder with CSWs, its deflection is increased by about 10% compared with the theoretical value of the elementary beam, and increased by about 1.87% compared with Timoshenko ’s theoretical value. As the span-to-height ratio increases gradually, the contribution of the full-section shear deformation effect to the deflection gradually decreases. With a smaller span-to-height ratio, a smaller shear stiffness of shear key, or a larger height ratio of sub-beams, shear deformation displays more significant effect on the vertical deflection of the structure, while the CSW type has little effect on the box deflection.