Analysis and Design Procedure for FRP-Strengthened Prestressed Concrete T-Girders Considering Strength and Fatigue
Publication: Journal of Composites for Construction
Volume 10, Issue 5
Abstract
Controlling the prestressing strand-stress range in precracked prestressed concrete girders is critical in the FRP strengthening process to avoid long-term fatigue failures. This paper will address the details of a design procedure that was developed to satisfy target-strengthening requirements while imposing stress range serviceability limits. Two main CFRP flexural strengthening designs were established for use in the experimental program herein. In the first, the amount of CFRP was designed to limit the average strand-stress range to , as per AASHTO requirements, under service live load while maintaining the service-ultimate moment relationship constant. The second design was intended to double the strand-stress range under service live load while keeping the same service-ultimate moment relationship. This was accomplished with iterative cycles of nonlinear sectional analysis to determine the amount of external CFRP reinforcement needed to yield both the targeted stress range and ultimate capacity. The girders were overly reinforced for shear with internal steel stirrups. However, external CFRP stirrups were used to prevent the longitudinal CFRP from premature separation and to develop full flexural capacity. The ACI 318-05 model for shear friction was used for this purpose. The paper also presents analysis results to qualify the experimental behavior of the tested girders. Load-deflection, load-strain, and moment-strand stress variations are seen to have excellent correlation with corresponding experimental curves. CFRP is shown to develop higher strains across cracks relieving strand stresses at these critical locations.
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Acknowledgments
This study was funded by the Kansas Department of Transportation and by the University Transportation Center at the University of Missouri, Rolla. CFRP strengthening materials were provided by Master Builders, Inc. Thanks are extended to Mr. Calvin E. Reed of Wilson and Company for several useful discussions.
References
AASHTO. (2004). LRFD bridge design specifications, 3rd Ed., American Association of State Highway Transportation Officials, Washington, D.C.
ACI 318-05. (2005). “Building code requirements for structural concrete and commentary.” ACI Committee 318, American Concrete Institute, Farmington Hills, Mich.
ACI 440.2R-02. (2002). “Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures.” ACI Committee 440, American Concrete Institute, Farmington Hills, Mich.
Bakis, C. E., Bank, L. C., Brown, V. L., Cosenza, E., Davalos, J. F., Lesko, J. J., Machida, A., Rizkalla, S. H., and Triantafillou, T. C. (2002). “Fiber-reinforced polymer composites for construction—State-of-the-art review.” J. Compos. Constr., 6(2), 73–87.
Chaallal, O., Nollet, M.-J., and Perraton, D. (1998). “Strengthening of reinforced concrete beams with externally bonded fiber-reinforced-plastic-plates: Design guidelines for shear and flexure.” Can. J. Civ. Eng., 25, 692–704.
El-Hacha, R., Wight, R. G., and Green, M. F. (2003). “Innovative system for prestressing fiber-reinforced polymer sheets.” ACI Struct. J., 100(3), 305–313.
El-Tawil, S., and Okeil, A. M. (2002). “LRFD flexural provisions for prestressed concrete bridge strengthened with carbon fiber-reinforced polymer laminates.” ACI Struct. J., 99(2), 181–190.
ISIS Canada. (2001). “Design manual 4: Strengthening reinforced concrete structures with externally-bonded fiber reinforced polymers.” Canadian Network of Centers of Excellence on Intelligent Sensing for Innovative Structures, University of Manitoba, Winnipeg, Manitoba.
Larson, K. H., Peterman, R. J., and Rasheed, H. A. (2005). “Strength-fatigue behavior of fiber-reinforced polymer strengthened prestressed concrete T-beams.” J. Compos. Constr., 9(4), 313–326.
Picard, A., Massicotte, B., and Boucher, E. (1995). “Strengthening of reinforced concrete beams with composite materials: Theoretical study.” Compos. Struct., 33, 63–75.
Precast/Prestressed Concrete Institute (PCI). (2004). PCI design handbook, 6th Ed., Chicago, Ill.
Rasheed, H. A., and Pervaiz, S. (2003). “Closed form design equations for flexural strengthening of RC beams.” Composites, Part B, 34(6), 539–550.
Reed, C. (2002). “Strengthening of old prestressed concrete bridge girders with carbon fiber reinforced polymers.” MS thesis, Kansas State University, Manhattan, Kan.
Saadatmanesh, H., and Malek, A. M. (1998). “Design guidelines for flexural strengthening of RC beams with FRP plates.” J. Compos. Constr., 2(4), 158–164.
Scanlon, A., and Murray, D. W. (1982). “Practical calculations of two-way slab deflections.” Concrete Int., Nov., 43–50.
Triantafillou, T. C., and Antonopoulos, C. P. (2000). “Design of concrete flexural members strengthened in shear with FRP.” J. Compos. Constr., 4(4), 198–205.
Wight, R. G., and Erki, M. A. (2003). “Prestressed CFRP sheets for strengthening concrete slabs in fatigue.” Adv. Struct. Eng., 6(3), 175–182.
Wu, Z. S., Iwashita, K., Hayashi, K., Higuchi, T., Murakami, S., and Koseki, Y. (2003). “Strengthening prestressed-concrete girders with externally prestressed PBO fiber reinforced polymer sheets.” J. Reinf. Plast. Compos., 22(14), 1269–1286.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 10 • Issue 5 • October 2006
Pages: 419 - 432
Copyright
© 2006 ASCE.
History
Received: Feb 5, 2004
Accepted: Mar 8, 2006
Published online: Oct 1, 2006
Published in print: Oct 2006
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