Estimation of The Shear-Lag Effect of Composite Box Girder Bridges With Corrugated Steel Webs

Abstract

The shear-lag effect refers to the non-uniform normal stress distribution on a box girder cross section induced by the shear flow at the flanges and the webs. It can be observed in all kinds of box girder structures especially the ones with a large width. The shear-lag effect has to be appropriately considered in bridge design, otherwise the servicability and reliability of a bridge will be reduced. In this paper, a semi-analytical method is proposed to estimate the shear-lag effect for composite box girder bridges with corrugated steel webs. Three generalized displacement functions are first introduced to represent the deformation patterns in different parts of a bridge cross section. Afterwards, the governing equations of the problem are derived based on the energy variance principle considering the feature of a composite box girder bridge with corurgated steel webs and then solved using the finite difference method. The shear-lag effect of a continuous girder bridge constructed in South China is investigated based on the proposed semi-analytical method and finite element simulation. The results show that the proposed semi-analytical method is able to well estimate the characteristics of the example bridge. Given the same bridge cross section, the magnitude of the shear-lag effect at different parts of the example bridge is inversely proportional to the effective span length.