Prediction of Shear Lag Effect in Thin-Walled Single-Box Multicell Box Girder Based on the Modified Warping Displacement Function

Xiayuan Li,Kongjian Shen,Peng Zhou,Xiao Wang,Shui Wan

doi:10.1155/2020/6815092

Abstract

In this study, an effective and accurate theoretical analysis method for predicting the shear lag effect in the thin-walled single-box multicell box girder is presented. The modifications of longitudinal warping displacement functions at the flanges are fully investigated, including the shear lag width (bij) of flanges, the coefficients (αij) of shear lag warping functions, the deformation compatibility conditions in flanges, and the internal force balance (D). The initial shear deformation (γ03) in the top lateral cantilever flanges is innovatively introduced in multicell box girders and obtained by the designed procedure. In addition, the transverse distribution function for describing the longitudinal warping displacement is deduced and expressed in the form of the cosine function. Based on the principle of minimum potential energy, the governing differential equations are derived and solved with the associated boundary and load conditions. The accuracy and applicability of the proposed method (SL-THY2) are validated for four thin-walled single-box multicell (two- and three-cell) box girders with the results derived from the solid finite element method.

Highlights

E objective of this study is to develop an effective and accurate theoretical analysis method for predicting the shear lag effect in thin-walled single-box multicell box girders
The deformation compatibility conditions in flanges are considered, and the correction factors are introduced and solved by the given equations. e initial shear deformation (c03) in the top lateral cantilever flanges is innovatively introduced in the multicell box girder and obtained by the designed procedure. e governing differential equations, based on the principle of minimum potential energy, are derived and solved with the associated boundary and load conditions
Modified Longitudinal Warping Displacement Functions e aim is to study the shear lag effect in thin-walled singlebox multicell box girders, as illustrated in Figure 1, where the loads are applied parallel to the middle plane of the webs uniformly in order to avoid torsion, distortion, and transverse bending of the cross section [2]. e components of the single-box multicell box girder are composed of basic elements: top and bottom central flanges, top lateral cantilever flanges, and webs. e x-axis is taken to coincide with the centroid axis along the beam span direction, and y- and z-axes are taken as the principal inertial directions

Summary

Introduction

E objective of this study is to develop an effective and accurate theoretical analysis method for predicting the shear lag effect in thin-walled single-box multicell box girders. To this end, the longitudinal warping displacement functions for the flanges are fully investigated. 2. Modified Longitudinal Warping Displacement Functions e aim is to study the shear lag effect in thin-walled singlebox multicell box girders, as illustrated, where the loads are applied parallel to the middle plane of the webs uniformly in order to avoid torsion, distortion, and transverse bending of the cross section [2]. Based on the above assumptions and the generation mechanism of shear lag phenomenon [22, 23], the longitudinal warping displacement functions in the flanges, including the constant contribution from bending according to Timoshenko beam theory (TBT) and the shear lag contribution, can be rationally written as [3, 4]

Methods

Findings

Conclusion