Improved Finite-Segment Method for Analyzing Shear Lag Effect in Thin-Walled Box Girders
Publication: Journal of Structural Engineering
Volume 138, Issue 10
Abstract
Shear lag effect in thin-walled box girders has been studied over several decades. However, the methods adopted in many papers have some deficiencies. In the present work, an improved displacement function for shear lag warping in a box girder with cantilever slabs is established. Based on the concept of generalized force corresponding to the generalized displacement for shear lag and the relevant geometrical properties, an improved finite-segment method is proposed to simplify the shear lag analysis of complex box girders. The homogeneous solution of the governing differential equation for shear lag is adopted as the element displacement function. The formulas of the element stiffness matrix and the equivalent nodal force vector are derived. A general formula expressed in terms of the generalized moment is presented to calculate the stress. A finite-element computer program is developed by using FORTRAN language and is used to analyze a cantilever box girder model and a continuous prestressed concrete box girder. The theoretical results are in good agreement with the test results, validating the proposed method and formulas. This paper also reveals for the first time the characteristics of the generalized moment for shear lag.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The author would like to gratefully acknowledge the financial support from the National Natural Science Foundation of China (Grant No. 51068018) and to thank Mr. Zhi-Guo Yang and Mrs. Hui Zhang for their constructive suggestions and assistance in preparing this manuscript. The present research is also supported by the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (IRT1139).
References
Chang, S. T. (2004). “Shear-lag effect in simply supported prestressed concrete box girder.” J. Bridge Eng., 9(2), 178–184.
Chang, S. T., Deng, X. H., and Wang, W. Z. (1998). Shear lag effect in thin-walled box girders, China Communications Press, Beijing, 111–132 (in Chinese).
Chang, S. T., and Yun, D. (1988). “Shear lag effect in box girder with varying depth.” J. Struct. Eng., 114(10), 2280–2292.
Chang, S. T., and Zheng, F. Z. (1987). “Negative shear lag in cantilever box girder with constant depth.” J. Struct. Eng., 113(1), 20–35.
Dezi, L., and Mentrasti, L. (1985). “Nonuniform bending-stress distribution (shear lag).” J. Struct. Eng., 111(12), 2675–2690.
Guo, J. Q., Fang, Z. Z., and Luo, X. D. (1983). “Analysis of shear lag effect in box girder bridge.” China Civ. Eng. J., 16(1), 1–13 (in Chinese).
Kuzmanovic, B. O., and Graham, H. J. (1981). “Shear lag in box girders.” J. Struct. Div., 107(9), 1701–1712.
Luo, Q. Z., and Li, Q. S. (2000). “Shear lag of thin-walled curved box girder bridges.” J. Eng. Mech., 126(10), 1111–1114.
Luo, Q. Z., Li, Q. S., Liu, D. K., and Yang, L. F. (2001). “A modified finite segment method for thin-walled single-cell box girders with shear lag.” Proc. ICE, Struct., Buildings, 146(1), 41–46.
Luo, Q. Z., Li, Q. S., and Tang, J. (2002a). “Shear lag in box girder bridges.” J. Bridge Eng., 7(5), 308–313.
Luo, Q. Z., Tang, J., and Li, Q. S. (2002b). “Finite segment method for shear lag analysis of cable-stayed bridges.” J. Struct. Eng., 128(12), 1617–1622.
Luo, Q. Z., Wu, Y. M., Li, Q. S., Tang, J., and Liu, G. D. (2004). “A finite segment model for shear lag analysis.” Eng. Struct., 26(14), 2113–2124.
Reissner, E. (1946). “Analysis of shear lag in box beams by the principle of the minimum potential energy.” Q. Appl. Math., 4(3), 268–278.
Wu, Y. P., Liu, S. Z., Zhu, Y. L., and Lai, Y. M. (2003). “Matrix analysis of shear lag and shear deformation in thin-walled box beams.” J. Eng. Mech., 129(8), 944–950.
Wu, Y. P., Yang, M., Zhou, D. W., Lin, L. X., and Su, Q. (2007). “Analysis of the shear lag effect on the top and bottom plates of box beams with varying loading locations.” China Civ. Eng. J., 40(10), 8–12 (in Chinese).
Zhang, Y. H., and Li, Q. (2009). “Flexural-torsional analysis of thin-walled curved box girders with shear lag and secondary shear deformation in restraint torsion.” China Civ. Eng. J., 42(3), 93–98 (in Chinese).
Zhou, S. J. (2008). “Shear lag analysis of box girders.” Eng. Mech., 25(2), 204–208 (in Chinese).
Zhou, S. J. (2010). “Finite beam element considering shear-lag effect in box girder.” J. Eng. Mech., 136(9), 1115–1122.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 138 • Issue 10 • October 2012
Pages: 1279 - 1284
Copyright
© 2012 American Society of Civil Engineers.
History
Received: Jan 16, 2011
Accepted: Dec 16, 2011
Published online: Dec 21, 2011
Published in print: Oct 1, 2012
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.