scholarly journals Effects of Shear Lag in Steel Box Girders of a Crane Runway

2020 ◽  
Vol 22 (1) ◽  
pp. 23-31
Author(s):  
Cătălin Moga ◽  
Delia Drăgan ◽  
Raluca Nerișanu
Keyword(s):  
Maximum Stress ◽  
Approximate Theory ◽  
Shear Lag ◽  
Box Girders ◽  
Box Girder ◽  
The Real ◽  
Lag Effect ◽  
Bending Stresses ◽  
Bending Of Beams

Abstract The term of shear lag is related to the discrepancies between the approximate theory of the bending of beams and their real behaviour. It refers to the increases of the bending stresses near the flange-to-web junctions and the corresponding decreases in the flange stresses away from these junctions. In the case of wide flanges of plated structures, shear lag caused by shear strains, which are neglected in the conventional theory, may be taken into account by a reduced flange width concentrated along the webs of the steel girders. In EN 1993-1-5, the concept of taking shear lag into account is based on effective width of the flange which is defined in order to have the same total normal force in the gross flange subjected to the real transverse stress distribution as the effective flange subjected to a uniform stress equal to the maximum stress of the real transverse distribution. Some aspects concerning the shear lag phenomenon and a working example for a box girder of a heavy crane runway to illustrate the determination of the shear lag effect are also presented.

scholarly journals A Shear Lag Analysis for Composite Box Girders with Deformable Connectors

10.14311/640 ◽  
2004 ◽  
Vol 44 (5-6) ◽  
Author(s):  
V. Křístek
Keyword(s):  
Harmonic Analysis ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Box Girders ◽  
Lag Effects ◽  
Lag Effect

A method is proposed for shear lag analysis which can be applied to steel-concrete composite box girders. The proposed method uses harmonic analysis and allows the determination of shear lag effects from simple calculations so that the method is regarded as a design aid. The character of the method can illustrate the influence of certain key parameters upon the extent of the shear lag effect. 

Analysis of Effect Factors about Shear Lag in Curved Box Girder under Seismic Loads

2014 ◽  
Vol 926-930 ◽  
pp. 505-510
Author(s):  
Hai Lin Lu ◽  
Li Peng Chen ◽  
Song Bo Zhu ◽  
Chong Yong Wan ◽  
Jia Qi Qian
Keyword(s):  
Finite Element ◽  
Curvature Radius ◽  
Seismic Load ◽  
Finite Element Models ◽  
Seismic Loads ◽  
Shear Lag ◽  
Effect Factors ◽  
Box Girders ◽  
Box Girder ◽  
Lag Effect

The shear lag effect will cause damage to the curved box girders. And it will adversely affect the bridge’s seismic performance. In order to analyze the effect under seismic loads, finite element models were created in this paper. By changing the parameters, such as curvature radius, width and height, their influence on the shear lag were studied. Results show that the effect was more obvious in wide and flat box girders under seismic load.

Shear-Lag Effects in Three-Span Continuous Box Girder

2011 ◽  
Vol 90-93 ◽  
pp. 2696-2704
Author(s):  
Yu Li Dong ◽  
Yuan Yuan Fang ◽  
Jun Li Lv
Keyword(s):  
Shear Stress ◽  
Abrupt Change ◽  
Reaction Force ◽  
Shear Stresses ◽  
Bending Stress ◽  
Shear Lag ◽  
Box Girder ◽  
The Real ◽  
Lag Effects ◽  
Bending Stresses

The physical explanation of shear lag is given in this paper. The shear lag effects can be attributed to the abrupt change of shear stress at web-flange junction. The abrupt change at the junction of shear stresses changes the magnitude of the flange bending stresses, which attenuates gradually with increasing distances from the web. Meanwhile, the abrupt change of shear stresses from zero to the flange shear stress also influences the bending stress state at the centerline of the flange. The method to determine the shear lag effects has been given, which is based on the Euler-Bernoulli elementary theory of bending, and the calculated results are in good agreement with the experimental results. Considering the transversal distribution of the shear stress at the junction, the flange real bending stress could be calculated on the section. The change of the shear stresses decreases the magnitude of the bending stresses in tension, but increases the magnitude of the bending stresses in compression. The shear lag effects in continuous box girder are different from that in the simply supported box girder. The reaction force of the continuous support would generate an abrupt change of the shear forces between the two sides of the support, and the real bending stresses beside the support would vary significantly due to shear lag effects. The ratio of real bending stress to standard bending stress is not the proper index to reflect the shear lag effects, but the real bending stresses could represent the shear lag effects and should be paid more attention to in design.

Analysis on Shear Lag Effect of Single Box and Double Cell Box Girders for Wei River Grand Bridge

2011 ◽  
Vol 121-126 ◽  
pp. 3145-3149
Author(s):  
Lei Sun ◽  
Xian Wu Hao ◽  
Kang Lei
Keyword(s):  
Normal Stress ◽  
Working Conditions ◽  
Element Model ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Box Girders ◽  
Box Girder ◽  
Rigid Frame ◽  
Lag Effect ◽  
Wei River

In order to study the influence of shear lag effect of single box and double cell box girder on structure，to make the rigid frame continuous bridge of Wei River grand bridge as the research object, through the establishment of finite element model, the normal stress and shear lag coefficient of the control sections in various working conditions is calculated, and the distribution of the box girder normal stress under shear lag effect is obtained.

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

2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Xiayuan Li ◽  
Shui Wan ◽  
Kongjian Shen ◽  
Peng Zhou ◽  
Xiao Wang
Keyword(s):  
Internal Force ◽  
Displacement Function ◽  
Force Balance ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Box Girders ◽  
Box Girder ◽  
Lag Effect ◽  
Warping Displacement ◽  
Thin Walled

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.

Geometric Nonlinear Analysis of Curved Box Continuous Girders Considering Shear Lag Effect

2011 ◽  
Vol 243-249 ◽  
pp. 1811-1816 ◽  
Author(s):  
Qi Zhi Luo ◽  
Yu Ji Chen
Keyword(s):  
Large Deflection ◽  
Computational Method ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Box Girders ◽  
Box Girder ◽  
Lag Effect ◽  
Thin Walled ◽  
Geometric Nonlinear Analysis ◽  
Good Agreement

The analytical theory and computational method for thin-walled curved box girders in terms of the shear lag effect and geometric nonlinearity are presented. Based on the potential variational principle and the theory of thin-walled box girders, the geometry nonlinear governing differential equations of thin-walled curved box girder considering the influence of the shear lag effect of flange’s stress and the large deflection is established. The equation is solved by means of Newton-Raphon iteration method. The results from the present method are in good agreement with those of the test and the segment method. The numerical examples are conducted to verify the accuracy and reliability of the present theories. It is shown that the proposed formulae and method could be referenced to the design for the thin-walled curved box girders considering shear lag effect.

Analysis on Shear Lag Effect of Box Girder Subject to Dynamic Load

2014 ◽  
Vol 501-504 ◽  
pp. 811-814 ◽  
Author(s):  
Yun Guo Zhang ◽  
Ying Nan Li
Keyword(s):  
Dynamic Load ◽  
Design Theory ◽  
Static Load ◽  
Great Influence ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Box Girders ◽  
Box Girder ◽  
Lag Effects ◽  
Lag Effect

Shear lag effect of box girders under static, transient dynamic load and harmonic dynamic load has been studied, respectively, through finite element method. Shear lag effects under different load conditions were compared and dynamic loading influence on shear lag was analyzed. The results show that the dynamic load has great influence on shear lag of thin box girder that can not be neglected. During the research, the eyesight was transfer from the conventional static load to the dynamic load to study the shear lag problem of box girder. The research conclusions will be useful for the design and construction of bridges and will enrich the design theory of box girder.

Shear lag effect on stress concentration in simply-supported stiffened box girder

2021 ◽  
Vol 183 ◽  
pp. 106715
Author(s):  
Eiki Yamaguchi ◽  
Naoto Kittaka ◽  
Buchit Maho ◽  
Piti Sukontasukkul
Keyword(s):  
Stress Concentration ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Box Girder ◽  
Simply Supported ◽  
Lag Effect

scholarly journals Computation of Deflections for PC Box Girder Bridges with Corrugated Steel Webs considering the Effects of Shear Lag and Shear Deformation

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Wei Ji ◽  
Kui Luo ◽  
Jingwei Zhang
Keyword(s):  
Shear Deformation ◽  
Prestressed Concrete ◽  
Displacement Function ◽  
Shear Lag ◽  
Longitudinal Displacement ◽  
Box Girders ◽  
Element Analysis ◽  
Box Girder ◽  
Bridge Model ◽  
Bridge Models

Prestressed concrete (PC) girders with corrugated steel webs (CSWs) have received considerable attention in the past two decades due to their light self-weight and high prestressing efficiency. Most previous studies were focused on the static behavior of CSWs and simple beams with CSWs. The calculation of deflection is an important part in the static analysis of structures. However, very few studies have been conducted to investigate the deflection of full PC girders or bridges with CSWs and no simple formulas are available for estimating their deflection under static loads. In addition, experimental work on full-scale bridges or scale bridge models with CSWs is very limited. In this paper, a formula for calculating the deflection of PC box girders with CSWs is derived. The longitudinal displacement function of PC box girders with CSWs, which can consider the shear lag effect and shear deformation of CSWs, is first derived. Based on the longitudinal displacement function, the formula for predicting the deflection of PC box girders with CSWs is derived using the variational principle method. The accuracy of the derived formula is verified against experimental results from a scaled bridge model and the finite element analysis results. Parametric studies are also performed, and the influences of shear lag and shear deformation on the deflection of the box girder with CSWs are investigated by considering different width-to-span ratios and different girder heights. The present study provides an effective and efficient tool for determining the deflection of PC box girders with CSWs.

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