Shear Lag in Thin-Walled Box Girder with Variable Section

2011 ◽  
Vol 194-196 ◽  
pp. 1165-1169
Author(s):  
Yu Hong Zhang ◽  
Zi Jiang Yang ◽  
Shi Zhong Liu
Keyword(s):  
Significant Influence ◽  
Width Ratio ◽  
Stiffness Ratio ◽  
Shear Lag ◽  
Box Girders ◽  
Box Girder ◽  
Lag Effects ◽  
Variable Section ◽  
Thin Walled ◽  
Span Width

In this paper, a equivalent-section method of analyzing shear lag effects in box girders is presented. The effect of two major parameters on shear lag is investigated for cantilever and continuous box girders with variable section under two kinds of loads. It is shown that the span-width ratio, in addition to the flange stiffness to total stiffness ratio, has a significant influence on the shear lag. Finally, conclusions are drawn with regard to further study and research.

scholarly journals Analysis of Pure Bending Vertical Deflection of Improved Composite Box Girders with Corrugated Steel Webs

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Chi Ma ◽  
Shi-zhong Liu ◽  
Jin Di ◽  
Rui-jie Zhang
Keyword(s):  
Shear Deformation ◽  
Analytical Solutions ◽  
Analytical Calculation ◽  
Load Condition ◽  
Width Ratio ◽  
Shear Lag ◽  
Vertical Deflection ◽  
Box Girders ◽  
Concentrated Load ◽  
Span Width

Steel bottom plates are applied as replacements for the concrete bottom plates in order to reduce the dead weight of the composite box girders with corrugated steel webs and steel bottom plates (CSWSB). Due to the change in the material, the previous analytical calculation methods of vertical deflection of composite box girders with corrugated steel webs (CSWs) cannot be directly applied to the improved composite box girders. The shear lag warpage displacement function was derived based on the shear deformation laws of the upper flange and the bottom plates of the improved composite box girders. The equations for the calculation of the shear deformation and the additional deflection due to the shear lag of continuous and simply supported composite box girders with CSWSB under concentrated and uniformly distribution loads were derived by considering the double effects of the shear lag and the shear deformations of the top and the bottom plates with different elastic moduli. The analytical solutions of the vertical deflection of the improved composite box girders include the theory of the bending deflection of elementary beams, shear deformation of CSWs, and the additional deflection caused by the shear lag. Based on the theoretical derivation, an analytical solution method was established and the obtained vertical deflection analytical solutions were compared with the finite element method (FEM) calculation results and the experimental values. The analytical equations of vertical deflection under the two supporting conditions and the two load cases have verified the analyses and the comparisons. Further, the additional deflections due to the shear lag and the shear deformation are found to be less than 2% and 34% of the total deflection values, respectively. Moreover, under uniform distributed load conditions, the deflection value was found to be higher than that of the under concentrated load condition. It was also found that the ratio of the deflection caused by the shear lag or the shear deformation to the total deflection decreased gradually with the increase in the span width ratio. When the value of the span width ratio of a single box and single chamber composite box girder with CSWSB was equal to or greater than 8, the deflections caused by the shear lag and the shear deformation could be ignored.

Study of Free Vibration Characteristic of Continuous Box-Girder Based on Hamilton Principle

2013 ◽  
Vol 351-352 ◽  
pp. 476-482 ◽  
Author(s):  
Wang Bao Zhou ◽  
Li Zhong Jiang ◽  
Zhi Huang
Keyword(s):  
Free Vibration ◽  
Natural Frequency ◽  
Width Ratio ◽  
Rotational Inertia ◽  
Shear Lag ◽  
Shear Lag Effect ◽  
Box Girder ◽  
Hamilton Principle ◽  
Lag Effect ◽  
Span Width

Based on Hamilton principle, the differential equation of free vibration and the corresponding boundary conditions of continuous box girder with consideration for the shear lag effect meeting self-equilibrated stress, shear deformation as well as rotational inertia were induced. The ANSYS finite element solutions were compared with the analytical solutions by calculation examples and the validity of the proposed approach was verified. The obtained formulas developed the shear lag theory. Some meaningful conclusions for engineering design were obtained. The contribution of the shear lag effect decreases each order natural frequency of the continuous box-girder, at the same time the higher the order natural frequency is, the greater the influence of shear lag effect on natural frequency of continuous box-girder is. The shear-lag effect of continuous box girder increases when frequency order rises, and increases while span-width ratio decreases.

Effect of Curvature Radius and Transverse Distribution of Load on Shear Lag for Curved Box Girders

2010 ◽  
Vol 163-167 ◽  
pp. 1555-1560
Author(s):  
Chang Feng Li ◽  
Wen Xue Du
Keyword(s):  
Coupling Effect ◽  
Curvature Radius ◽  
Curved Beam ◽  
Fundamental Theory ◽  
Shear Lag ◽  
Box Girders ◽  
Box Girder ◽  
Transverse Distribution ◽  
Thin Walled ◽  
The Galerkin Method

Based on fundamental theory and variational principle of thin-walled curved beam and taking into account of coupling effect of bend and shear lag, the paper mainly discusses the variation of curvature radius and the transverse distribution of load in order to analyze effect of shear lag in curved box girder. By means of variational method, the paper derivates the elastic differential equation and boundary conditions and gives numerical results of equations finally, results are obtained by the Galerkin method. It shows that the curvature radius and the transverse distribution of load in the shear lag of curved box girder is very important by comparing the calculating results.

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.

Beam finite element for thin-walled box girders considering shear lag and shear deformation effects

2021 ◽  
Vol 233 ◽  
pp. 111867
Author(s):  
Xiayuan Li ◽  
Shui Wan ◽  
Yuanhai Zhang ◽  
Maoding Zhou ◽  
Yilung Mo
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Shear Lag ◽  
Box Girders ◽  
Thin Walled

Static response of curved steel thin-walled box-girder bridge subjected to Indian railway loading

2021 ◽  
Vol 108 (2) ◽  
pp. 63-74
Author(s):  
V. Verma ◽  
K. Nallasivam
Keyword(s):  
Finite Element ◽  
Dynamic Response ◽  
Box Girders ◽  
Box Girder ◽  
One Dimensional ◽  
Thin Walled ◽  
Box Girder Bridge ◽  
Girder Bridge ◽  
Indian Railway ◽  
Different Response

Purpose: The primary objective of the current study is to numerically model the steel thin-walled curved box-girder bridge and to examine its various response parameters subjected to Indian Railway loading. Design/methodology/approach: The analysis is conducted by adopting a one dimensional curved thin-walled box-beam finite beam element based on finite element methodology. The scope of the work includes a computationally efficient, three-noded, one-dimensional representation of a thin-walled box-girder bridge, which is especially desirable for its preliminary analysis and design phase, as well as a study of the static characteristics of a steel curved bridge, which is critical for interpreting its dynamic response. Findings: The analytical results computed using finite element based MATLAB coding are presented in the form of various stress resultants under the effect of various combinations of Indian Railway loads. Additionally, the variation in different response parameters due to changes in radius and span length has also been investigated. Research limitations/implications: The research is restricted to the initial design and analysis phase of box-girder bridge, where the wall thickness is small as compared to the cross-section dimensions. The current approach can be extended to future research using a different method, such as Extended finite element technique on curved bridges by varying boundary conditions and number of elements. Originality/value: The validation of the adopted finite element approach is done by solving a numerical problem, which is in excellent agreement with the previous research findings. Also, previous studies had aimed at thin-walled box girders that had been exposed to point loading, uniformly distributed loading, or highway truck loading, but no research had been done on railway loading. Moreover, no previous research had performed the static analysis on thin-walled box-girders with six different response parameters, as the current study has. Engineers will benefit greatly from the research as it will help them predict the static behaviour of the curved thin-walled girder bridge, as well as assess their free vibration and dynamic response analysis.

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.

Study on the Shear Lag Effect of the PC Box Girder Bridge with Corrugated Steel Webs under Concentrated Loads

2014 ◽  
Vol 644-650 ◽  
pp. 5054-5060
Author(s):  
Rui Juan Jiang ◽  
Yu Feng Xiao ◽  
Xiao Wei Yi ◽  
Qi Ming Wu ◽  
Wei Ming Gai
Keyword(s):  
Shear Lag ◽  
Shear Lag Effect ◽  
Element Analysis ◽  
Box Girder ◽  
Current Time ◽  
Lag Effects ◽  
Lag Effect ◽  
Box Girder Bridge ◽  
Girder Bridge ◽  
Effective Flange Width

There are few studies about the shear lag effect and the effective flange width of the PC (Prestressed Concrete) box girder bridge with corrugated steel webs throughout the world in current time. In the present paper, based on the three-dimensional finite element analysis for a long-span continuous PC box girder bridge with corrugated steel webs and the corresponding conventional box girder bridge with concrete webs, a comparative study on the shear lag effect under vertical loads are carryied out together with the analyslis on the coefficient of the effective flange width. The results show that in the PC box girder with corrugated steel webs, the transverse distributions of longitudinal normal stress on the section of the slabs are obviousely non-uniform and they are different with those in the conventional PC box girder with concrete webs. And moreover, the shear lag effects in top slab of the PC box girder with corrugated steel webs are almost less obvious than those of the conventional PC box girder with concrete webs. However, the shear lag effects in bottom slab of the PC box girder with corrugated steel webs are almost similar to those of the conventional PC box girder with concrete webs, no matter what kind of vertical bending moment the cross section is subjected to

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