In- and Out-of-Plane Bending in Steel Through-Truss Bridges
Publication: Practice Periodical on Structural Design and Construction
Volume 27, Issue 2
Abstract
Steel through-truss is a very common configuration for railroad and highway bridges. There is a large number of such spans in surface transportation infrastructure worldwide, especially in railway systems. In design and evaluation, these spans’ in- and out-of-plane bending have been either omitted or approximated. A fuller understanding of this effect will be able to assist in reliably designing and assessing these structures for longevity and/or increasing allowable service load to facilitate economic developments. A full scale load test is performed in this paper on five such bridges of the Canadian National Railway (CN) using train load. The main truss elements prone to in- and out-of-plane bending are identified and strain-gauged including the hanger (L1U1 or L’1U’1). Out-of-plane bending is seen to produce more significant flexural stress than in-plane bending. Three-dimensional (3D) numerical simulation is also verified by physical tests and covers other uninstrumented members of the tested spans. These results are used to evaluate the accuracy of a new and simplifying two-dimensional (2D) analysis method for the most significantly bent vertical hanger out-of-plane. The 2D method is shown to capture a significant portion of the bending but still underestimate flexural stress. An empirical and hybrid approach is therefore developed and recommended to address the inadequately accounted out-of-plane bending for routine practice of design and evaluation. It is needed when resources for detailed 3D analysis are not readily available, and/or when a quick and reliable method is needed, e.g., for verification or calibration of another method. These results are also useful for stress range estimation for fatigue analysis, although fatigue is not a concern to these bridges and is therefore not specifically addressed in this paper. CN has adopted the recommended method and the other research findings in load-rating their existing through-truss bridges.
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Data Availability Statement
All data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
Mr. Hoat Le has contributed to the load tests reported herein and his advice and efforts are acknowledged with gratitude of the authors. Funding of Canadian National Railway and Illinois Institute of Technology are gratefully appreciated.
References
Azizinamini, A. 2002. “Full scale testing of old steel truss bridge.” J. Constr. Steel Res. 58 (5–8): 843–858. https://doi.org/10.1016/S0143-974X(01)00096-7.
Baniya, S. 2015.“Modeling and analysis of a steel truss railroad bridge traversed by trains at various speeds.” Master’s theses, Dept. of Civil Environmental Engineering, Univ. of Connecticut.
De Luca, A. 1981. “Estimated fatigue damage in a railway truss bridge: An analytical and experimental evaluation.” Theses and dissertations, Dept. of Civil Engineering, Lehigh Univ.
Fu, G. 2013. Bridge design and evaluation: LRFD and LRFR. Washington, DC: Wiley.
Goslin, K., and W. Davids. 2014. Advanced bridge safety initiative: Investigation of floor beam performance in three steel through-truss bridges. Augusta, ME: Univ. of Maine.
O’Connell, H. M., and R. J. Dexter. 2001. “Response and analysis of steel trusses for fatigue truck loading.” J. Bridge Eng. 6 (6): 628–638. https://doi.org/10.1061/(ASCE)1084-0702(2001)6:6(628).
Reis, E. D., D. L. C. E. Souza, H. Carvalho, P. A. Montenegro, and D. Ribeiro. 2021.“Structural Safety and Stability of the Bridge on the Paraopeba River in Moeda, Minas Gerais, Brazil: Case Study.” Pract. Period. Struct. Des. Constr. 26 (1): 05020012. https://doi.org/10.1061/(ASCE)SC.1943-5576.0000529.
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© 2022 American Society of Civil Engineers.
History
Received: Aug 11, 2021
Accepted: Nov 3, 2021
Published online: Jan 31, 2022
Published in print: May 1, 2022
Discussion open until: Jun 30, 2022
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