Higher Level Evaluation of a Reinforced Concrete Slab Bridge
Publication: Journal of Bridge Engineering
Volume 15, Issue 2
Abstract
In New Mexico, many reinforced concrete slab (RCS) bridges provide service on interstates I-10, I-25, and I-40. The load rating for this type of bridge largely depends on the live-load moment in the slab. Consequently, the objective of this study was to determine a more accurate value for the equivalent strip width using higher level evaluation techniques. A continuous RCS bridge was evaluated starting with an AASHTO load and resistance factor rating analysis. A diagnostic test was then conducted to measure live-load strains which showed that the slab stiffness fit within cracked and gross section behavior. Furthermore, slab moments from finite element analysis agreed reasonably well with experimental moments derived using the average of the cracked and gross section modulus. From refined analysis, the equivalent strip widths for positive moment were 26.1 and 22.1% greater than those calculated by the AASHTO approximate method for the exterior and interior spans, respectively. The refined widths for negative moment were greater than AASHTO by 13.1 and 11.1%. This increase in the equivalent strip width reduced the live-load effects, which proportionally increased the rating factors.
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Acknowledgments
The writers thank the NMDOT Research Bureau for providing financial support to conduct this research project. The NMSU research team would also like to acknowledge the advice and review provided by Mr. Jimmy Camp (State Bridge Engineer, NMDOT), Dr. Steve Maberry (Bridge Rating Engineer, NMDOT), Mr. Jeff Vigil (Bridge Management Engineer, NMDOT), and Mr. Wil Dooley (Division Bridge Engineer, FHWA). The management provided by Mr. Rais Rizvi (Research Engineer, NMDOT) and Mr. Virgil Valdez (Research Analyst, NMDOT) is also greatly appreciated. Last, the writers thank Mr. Earl Franks (Bridge Engineer, NMDOT) and the bridge crew from NMDOT District I for their assistance in the field testing.
References
AASHTO. (2003). Manual for condition evaluation and load and resistance factor rating (LRFR) of highway bridges, AASHTO, Washington, D.C.
AASHTO. (2004). Load and resistance factor design (LRFD) bridge design specifications, 3rd Ed., AASHTO, Washington, D.C.
Amer, A., Arockiasamy, M., and Shahawy, M. (1999). “Load distribution of existing solid slab bridges based on field tests.” J. Bridge Eng., 4(3), 189–193.
Bell, E. S., Brenner, B., Sanayei, M., and Lattanzi, D. (2006). “Defining baseline model for bridge analysis and design.” Proc., 85th Annual Meeting of the Transportation Research Board, TRB, National Research Council, Washington, D.C.
Bridge Diagnostics, Inc. (BDI). (2005). Structural testing system II operation manual, BDI, Boulder, Colo.
Chajes, M. J., Shenton, H. W., III, and O’Shea, D. (1999). “Use of field testing in Delaware’s bridge management program.” Proc., 8th Int. Bridge Management Conf., TRB, National Research Council, Denver, Colo.
Commander, B., and Schulz, J. (1997). “A field verified load rating method for reinforced concrete slab bridges.” Proc., ASCE Structures Congress XV (Building to Last), ASCE, Structural Engineering Institute, Portland, Ore.
Computers and Structures, Inc. (CSI). (2006). “Integrated finite element analysis and design of structures.” SAP2000, Berkeley, Calif.
Federal Highway Administration (FHWA). (1995). “Recording and coding guide for the structure inventory and appraisal of the nation’s bridges.” FHWA-PD-96-0001, United States Department of Transportation, Washington, D.C.
Federal Highway Administration (FHWA). (2007). “Tables of frequently requested NBI information.” National Bridge Inventory (NBI), United States Department of Transportation, Washington, D.C., ⟨http://www.fhwa.dot.gov/bridge/britab.htm⟩ (Nov. 1, 2007).
Licon-Lozano, A. (2007). “Non-destructive strength evaluation of a continuous, reinforced concrete slab bridge.” MS thesis, New Mexico State Univ., Las Cruces, N.M.
Mabsout, M., Tarhini, K., Jabakhanji, R., and Awwad, E. (2004). “Wheel load distribution in simply supported concrete slab bridges.” J. Bridge Eng., 9(2), 147–155.
New Mexico Department of Transportation (NMDOT). (2005). “Routine bridge inspection report.” Bridge 7270 Inspection Rep. No. M-212, Bridge Design Bureau, Santa Fe, N.M.
Saraf, V. K. (1998). “Evaluation of existing RC slab bridges.” J. Perform. Constr. Facil., 12(1), 20–24.
Wipf, T. J., Phares, B. M., Klaiber, F. W., Wood, D. L., Mellingen, E., and Samuelson, A. (2003). “Development of bridge load testing process for load evaluation.” Rep. No. TR-445, Center for Transportation Research and Education, Iowa State Univ.
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© 2010 ASCE.
History
Received: Aug 11, 2008
Accepted: Mar 31, 2009
Published online: May 15, 2009
Published in print: Mar 2010
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