A modified finite segment method for thin-walled single-cell box girders with shear lag

The homogeneous solutions of the governing differential equations for shear lag are used as the displacement patterns of the finite segment are presented. A finite segment model with consideration of initial curvature, bending, torsion and shear lag is established. In addition, the tests of the two-span continuous curved box girder and numerical calculations of the model tests by finite segment method and finite element method are made. The results of the model tests and numerical calculation are consistent with each other. An actual example was given to investigate the shear lag effect of a continuous curved box girder under load. The research results show that the initial curvature has an obvious influence on the shear lag effect of a continuous curved box girder.

Download Full-text

The stochastic finite segment in the analysis of the shear-lag effect on box-girders

Engineering Structures ◽

10.1016/s0141-0296(01)00045-1 ◽

2001 ◽

Vol 23 (11) ◽

pp. 1461-1468 ◽

Cited By ~ 8

Author(s):

L.F. Yang ◽

A.Y.T. Leung ◽

Q.S. Li

Keyword(s):

Shear Lag ◽

Shear Lag Effect ◽

Box Girders ◽

Finite Segment ◽

Lag Effect

Download Full-text

Shear Lag in Thin-Walled Box Girder with Variable Section

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.194-196.1165 ◽

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.

Download Full-text

Improved method for shear lag analysis of thin-walled box girders considering axial equilibrium and shear deformation

Thin-Walled Structures ◽

10.1016/j.tws.2020.106732 ◽

2020 ◽

Vol 151 ◽

pp. 106732

Author(s):

Xiaoyang He ◽

Yiqiang Xiang ◽

Zhengyang Chen

Keyword(s):

Shear Deformation ◽

Shear Lag ◽

Improved Method ◽

Box Girders ◽

Thin Walled

Download Full-text

A Finite Segment Method for Skewed Box Girder Analysis

Mathematical Problems in Engineering ◽

10.1155/2018/2592613 ◽

2018 ◽

Vol 2018 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Xingwei Xue ◽

Jiawei Wu ◽

Junlong Zhou ◽

Hongnan Li

Keyword(s):

Three Dimensional ◽

Beam Element ◽

Dimensional Structure ◽

Elastic Displacement ◽

Box Girders ◽

Box Girder ◽

Significant Saving ◽

Finite Segment ◽

Skew Plate ◽

Finite Segment Method

A finite segment method is presented to analyze the mechanical behavior of skewed box girders. By modeling the top and bottom plates of the segments with skew plate beam element under an inclined coordinate system and the webs with normal plate beam element, a spatial elastic displacement model for skewed box girder is constructed, which can satisfy the compatibility condition at the corners of the cross section for box girders. The formulation of the finite segment is developed based on the variational principle. The major advantage of the proposed approach, in comparison with the finite element method, is that it can simplify a three-dimensional structure into a one-dimensional structure for structural analysis, which results in significant saving in computational times. At last, the accuracy and efficiency of the proposed finite segment method are verified by a model test.

Download Full-text

Distributed Deformation Monitoring for a Single-Cell Box Girder Based on Distributed Long-Gage Fiber Bragg Grating Sensors

Sensors ◽

10.3390/s18082597 ◽

2018 ◽

Vol 18 (8) ◽

pp. 2597 ◽

Cited By ~ 2

Author(s):

Sheng Shen ◽

Shao-Fei Jiang

Keyword(s):

Single Cell ◽

Fiber Bragg Grating ◽

Maximum Error ◽

Deformation Monitoring ◽

Bragg Grating ◽

Shear Lag ◽

Box Girders ◽

Box Girder ◽

Hollow Beam ◽

Fiber Bragg Grating Sensors

Distributed deformation based on fiber Bragg grating sensors or other kinds of strain sensors can be used to monitor bridges during operation. However, most research on distributed deformation monitoring has focused on solid rectangular beams rather than box girders—a kind of typical hollow beam widely employed in actual bridges. The deformation of a single-cell box girder contains bending deflection and also two additional deformations respectively caused by shear lag and shearing action. This paper revises the improved conjugated beam method (ICBM) based on the long-gage fiber Bragg grating (LFBG) sensors to satisfy the requirements for monitoring the two additional deformations in a single-cell box girder. This paper also proposes a suitable LFBG sensor placement in a box girder to overcome the influence of strain fluctuation on the flange caused by the shear lag effect. Results from numerical simulations show that the theoretical monitoring errors of the revised ICBM are typically 0.3–1.5%, and the maximum error is 2.4%. A loading experiment for a single-cell box gilder monitored by LFBG sensors shows that most of the practical monitoring errors are 6–8% and the maximum error is 11%.

Download Full-text