Title:
Effect of Combining Near-Surface-Mounted and U-Wrap Fiber-Reinforced Polymer Strengthening Techniques on Behavior of Reinforced Concrete Beams
Author(s):
Rahulreddy Chennareddy and Mahmoud M. Reda Taha
Publication:
Structural Journal
Volume:
114
Issue:
3
Appears on pages(s):
719-728
Keywords:
ductility; fiber-reinforced polymers (FRPs); near-surface mounting; U-wrap shear strengthening
DOI:
10.14359/51689443
Date:
5/1/2017
Abstract:
Flexural strengthening of reinforced concrete (RC) beams using near-surface-mounted (NSM) fiber-reinforced polymers (FRP) and U-wrap FRP shear strengthening are two well-established methods. There is a fair chance that the two aforementioned techniques might be mixed in strengthening of RC beams. This research examines the behavior of RC beams strengthened using NSM and U-wrap FRP strengthening. The NSM-FRP flexural strengthening technique is strongly dependent on the performance of bond between the NSM-FRP bar and the surrounding epoxy. Tension rupture of the NSM-FRP bar is highly unlikely, even when a full development length is provided. However, when U-wrap FRP is considered, confinement has shown to improve the bond strength of NSM-FRP bars and marginally increase the flexural capacity of strengthened RC beams. However, the improvement in the bond strength of NSM-FRP bars results in changing the NSM-FRP debonding to an abrupt failure caused by NSM-FRP bar rupture. Special care should be taken in designing RC strengthening combining NSM and U-wrap FRP strengthening.
Related References:
1. Hermann, A. W., “American’s Infrastructure: 2013 Report Card,” IABSE Symposium Report, V. 99, No. 33, International Association for Bridge and Structural Engineering, 2013.
2. Huang, R. Y.; Mao, I.; and Lee, H. K., “Exploring the Deterioration Factors of RC Bridge Decks: A Rough Set Approach,” Computer-Aided Civil and Infrastructure Engineering, V. 25, No. 7, 2010, pp. 517-529. doi: 10.1111/j.1467-8667.2010.00665.x
3. Bakis, C.; Bank, L. C.; Brown, V.; Cosenza, E.; Davalos, J.; Lesko, J.; Machida, A.; Rizkalla, S. H.; and Triantafillou, T. C., “Fiber-Reinforced Polymer Composites for Construction-State-of-the-Art Review,” Journal of Composites for Construction, ASCE, V. 6, No. 2, 2002, pp. 73-87. doi: 10.1061/(ASCE)1090-0268(2002)6:2(73)
4. Saadatmanesh, H., and Ehsani, M., “Fiber Composite Plates Can Strengthen Beams,” Concrete International, V. 12, No. 3, Mar. 1990, pp. 65-71.
5. Nanni, A.; Alkhrdaji, T.; Barker, M.; Chen, G.; Mayo, R.; and Yang, X., “Overview of Testing to Failure Program of a Highway Bridge Strengthened with FRP Composites,” Proceedings of the 4th International Symposium on Non-Metallic (FRP) Reinforcement for Concrete Structures (FRPRCS-4), Baltimore, MD, 1999, pp. 69-75.
6. De Lorenzis, L., and Teng, J., “Near-Surface Mounted FRP Reinforcement: An Emerging Technique for Strengthening Structures,” Composites. Part B, Engineering, V. 38, No. 2, 2007, pp. 119-143. doi: 10.1016/j.compositesb.2006.08.003
7. Hassan, T. K., and Rizkalla, S. H., “Bond Mechanism of Near-Surface-Mounted Fiber-Reinforced Polymer Bars for Flexural Strengthening of Concrete Structures,” ACI Structural Journal, V. 101, No. 6, Nov.-Dec. 2004, pp. 830-839.
8. Yan, X.; Miller, B.; Nanni, A.; and Bakis, C., “Characterization of CFRP Rods Used as Near Surface Mounted Reinforcement,” 8th International Conference on Structural Faults and Repair, Edinburgh, Scotland, 1999.
9. De Lorenzis, L.; Lundgren, K.; and Rizzo, A., “Anchorage Length of Near-Surface Mounted Fiber-Reinforced Polymer Bars for Concrete Strengthening-Experimental Investigation and Numerical Modeling,” ACI Structural Journal, V. 101, No. 2, Mar.-Apr. 2004, pp. 375-386.
10. Lorenzis, L. D., and Nanni, A., “Characterization of FRP Rods as Near-Surface Mounted Reinforcement,” Journal of Composites for Construction, ASCE, V. 5, No. 2, 2001, pp. 114-121. doi: 10.1061/(ASCE)1090-0268(2001)5:2(114)
11. ACI Committee 440, “Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures (ACI 440.2R-08),” American Concrete Institute, Farmington Hills, MI, 2008, 76 pp.
12. Chajes, M. J.; Januszka, T. F.; Mertz, D. R.; Thomson, T. A. Jr.; and Finch, W. W. Jr., “Shear Strengthening of Reinforced Concrete Beams Using Externally Applied Composite Fabrics,” ACI Structural Journal, V. 92, No. 3, May-June 1995, pp. 295-303.
13. Malvar, L.; Warren, G.; and Inaba, C., “Rehabilitation of Navy Pier Beams with Composite Sheets,” RILEM Proceedings, Chapman and Hall, 1995, pp. 533-540.
14. Kachlakev, D., and McCurry, D., “Behavior of Full-Scale Reinforced Concrete Beams Retrofitted for Shear and Flexural with FRP Laminates,” Composites. Part B, Engineering, V. 31, No. 6, 2000, pp. 445-452. doi: 10.1016/S1359-8368(00)00023-8
15. Augustine, F. W., “Strengthening Rectangular Beams with NSM Steel Bars and Externally Bonded GFRP,” master’s thesis, Kansas State University, Manhattan, KS, 2013.
16. Naaman, A., and Jeong, S. M., “Structural Ductility of Concrete Beams Prestressed with FRP Tendons. In Non-Metric (FRP) Reinforcement for Concrete Structures,” Proceedings of the 2nd International RILEM Symposium (FRPRCS-2), Ghent, Belgium, Aug. 23-25 1995, pp. 379-386.
17. Jaeger, L.; Mufti, A.; and Tadros, G., “The Concept of the Overall Performance Factor in Rectangular-Section Reinforced Concrete Members,” Proceedings of the 3rd International Symposium on Non-Metallic (FRP) Reinforcement for Concrete Structures, Sapporo, Japan, 1997, pp. 551-559.
18. Zou, P. X. W., “Flexural Behavior and Deformability of Fiber Reinforced Polymer Prestressed Concrete Beams,” Journal of Composites for Construction, ASCE, V. 7, No. 4, 2003, pp. 275-284. doi: 10.1061/(ASCE)1090-0268(2003)7:4(275)
19. Abdelrahman, A. A.; Tadros, G.; and Rizkalla, S. H., “Test Model for First Canadian Smart Highway Bridge,” ACI Structural Journal, V. 92, No. 4, July-Aug. 1995, pp. 451-458.
20. Dongkeun, L.; Lijuan, C.; and Jason Yan-Gee, H., “Bond Characteristics of Various NSM FRP Reinforcements in Concrete,” Journal of Composites for Construction, V. 17, No. 1, 2012, pp. 117-129.
21. Kotynia, R., “Debonding Failures of RC Beams Strengthened with Externally Bonded Strips,” Proceedings of the International Symposium on Bond Behaviour of FRP in Structures (BBFS 2005), 2005.
22. Chen, C., and Cheng, L., “Fatigue Bond Characteristics and Degradation of Near-Surface Mounted CFRP Rods and Strips in Concrete,” Journal of Composites for Construction, ASCE, V. 18, No. 2, 2015