Title:
Use of Anchored Carbon Fiber-Reinforced Polymer Strips for Shear Strengthening of Large Girders
Author(s):
William A. Shekarchi, Wassim M. Ghannoum, and James O. Jirsa
Publication:
Structural Journal
Volume:
115
Issue:
1
Appears on pages(s):
281-291
Keywords:
carbon-fiber reinforced polymer (CFRP); CFRP anchors; reinforced concrete (RC); shear behavior; shear strengthening
DOI:
10.14359/51701092
Date:
1/1/2018
Abstract:
The objective of this research was to investigate the feasibility of increasing the shear capacity of large reinforced concrete girders using anchored carbon fiber-reinforced (CFRP) strips. In an experimental study consisting of nine tests, the effects of unidirectional and bidirectional CFRP layouts, anchored and fully wrapped systems, retrofitting uncracked and precracked sections, and loading conditions on the shear performance of large girders with relatively wide webs were investigated. Test results indicated that CFRP anchors were able to develop the fracture strength of the CFRP strips despite some anchors being placed in flexural tension zones. The unidirectional CFRP layouts were able to improve the shear capacity by as much as 56% while the bidirectional layouts improved the inclined cracking shear load by as much as 22%. Moreover, the measured lower-bound average CFRP fracture strain was found to be significantly larger (0.007) than the maximum permitted effective strain (0.004) currently recommended for design.
Related References:
1. 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, 80 pp.
2. Khalifa, A., and Nanni, A., “Rehabilitation of Rectangular Simply Supported RC Beams with Shear Deficiencies Using CFRP Composites,” Construction and Building Materials, V. 16, No. 3, 2002, pp. 135-146. doi: 10.1016/S0950-0618(02)00002-8
3. Zhang, Z., and Hsu, C. T. T., “Shear Strengthening of Reinforced Concrete Beams using Carbon-Fiber-Reinforced Polymer Laminates,” Journal of Composites for Construction, ASCE, V. 9, No. 2, 2005, pp. 158-169. doi: 10.1061/(ASCE)1090-0268(2005)9:2(158)
4. Pellegrino, C., and Modena, C., “Fiber-Reinforced Polymer Shear Strengthening of Reinforced Concrete Beams: Experimental Study and Analytical Modeling,” ACI Structural Journal, V. 103, No. 5, Sept.-Oct. 2006, p. 720-728.
5. Aridome, Y.; Kanakubo, T.; Furuta, T.; and Matsui, M., “Ductility of T-Shape RC Beams Strengthened by CFRP Sheet U-anchor,” Transactions of the Japan Concrete Institute, V. 20, 1998, pp. 117-124.
6. Ortega, C. A.; Belarbi, A.; and Bae, S. W., “End Anchorage of Externally Bonded FRP Sheets for the Case of Shear Strengthening of Concrete Girders,” Proceedings of the 9th International Symposium on Fiber Reinforced Polymer Reinforcement for Concrete Structures (FRPRCS-9), Thomas Telford, London, UK, 2009.
7. Deifalla, A., and Ghobarah, A., “Strengthening RC T-Beams Subjected to Combined Torsion and Shear Using FRP Fabrics: Experimental Study,” Journal of Composites for Construction, ASCE, V. 14, No. 3, 2010, pp. 301-311. doi: 10.1061/(ASCE)CC.1943-5614.0000091
8. Orton, S. L.; Jirsa, J. O.; and Bayrak, O., “Design Considerations of Carbon Fiber Anchors,” Journal of Composites for Construction, ASCE, V. 12, No. 6, 2008, pp. 608-616. doi: 10.1061/(ASCE)1090-0268(2008)12:6(608)
9. Huaco, G. D.; Jirsa, J. O.; and Bayrak, O., “Quality Control Test for Carbon Fiber Reinforced Polymer (CFRP) Anchors for Rehabilitation,” Tenth International Symposium on Fiber-Reinforced Polymer Reinforcement for Concrete Structures, SP-275, American Concrete Institute, Farmington Hills, MI, 2011, pp. 1-18.
10. Kim, Y.; Quinn, K. T.; Satrom, C. N.; Garcia, J.; Sun, W.; Ghannoum, W. M.; and Jirsa, J. O., “Shear Strengthening of Reinforced and Prestressed Concrete Beams Using Carbon Fiber Reinforced Polymer (CFRP) Sheets and Anchors,” FHWA/TX-12/0-6306-1, Center for Transportation Research, Austin, TX, 2012, 325 pp.
11. Koutas, L., and Triantafillou, T. C., “Use of Anchors in Shear Strengthening of Reinforced Concrete T-Beams with FRP,” Journal of Composites for Construction, ASCE, V. 17, No. 1, 2013, pp. 101-107. doi: 10.1061/(ASCE)CC.1943-5614.0000316
12. Kim, Y.; Quinn, K.; Ghannoum, W. M.; and Jirsa, J. O., “Strengthening of Reinforced Concrete T-Beams Using Anchored CFRP Materials,” ACI Structural Journal, V. 111, No. 5, Sept.-Oct. 2014, p. 1027 doi: 10.14359/51686805
13. Kim, Y.; Ghannoum, W. M.; and Jirsa, J. O., “Shear Behavior of Full-Scale Reinforced Concrete T-Beams Strengthened using CFRP Strips and Anchors,” Construction and Building Materials, V. 94, June 2015, pp. 1-9.
14. Jirsa, J. O.; Ghannoum, W. M.; Kim, C.; Sun, W.; Shekarchi, W.; Alotaibi, N.; Pudleiner, D. K.; Zhu, J.; Liu, S.; and Wang, H., “Use of Carbon Fiber Reinforced Polymer (CFRP) with CFRP Anchors for Shear-Strengthening and Design Recommendations/Quality Control Procedures for CFRP Anchors,” FHWA/TX-16/0-6783-R1D, Center for Transportation Research, Austin, TX, 2016, 232 pp.
15. ACI Committee 318, “Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary (ACI 318R-14),” American Concrete Institute, Farmington Hills, MI, 2014, 520 pp.
16. American Association of State Highway and Transportation Officials, “AASHTO LRFD Bridge Design Specifications,” seventh edition, Washington, DC, 2014, 2150 pp.
17. Sun, W., and Ghannoum, W. M., “Modeling of Anchored CFRP Strips Bonded to Concrete,” Construction and Building Materials, V. 85, March 2015, pp. 144-156. doi: 10.1016/j.conbuildmat.2015.03.096
18. Sun, W.; Jirsa, J. O.; and Ghannoum, W. M., “Behavior of Anchored Carbon Fiber-Reinforced Polymer Strips Used for Strengthening Concrete Structures,” ACI Materials Journal, V. 113, No. 2, Mar.-Apr. 2016, pp. 163-172. doi: 10.14359/51688637
19. Sokoli, D.; Shekarchi, W. A.; Buenrostro, E.; and Ghannoum, W. M., “Advancing Behavioral Understanding and Damage Evaluation of Concrete Members Using High-Resolution Digital Image Correlation Data,” Earthquakes and Structures, V. 7, No. 5, 2014, pp. 609-626. doi: 10.12989/eas.2014.7.5.609
20. Shekarchi, W. A., “Shear Behavior of Reinforced Concrete Bridge Pile Cap Girders Strengthened with Carbon Fiber Reinforced Polymer (CFRP) Strips and CFRP Anchors,” PhD dissertation, The University of Texas at Austin, Austin, TX, 2016, 317 pp.
21. Triantafillou, T. C., and Antonopoulos, C. P., “Design of Concrete Flexural Members Strengthened in Shear with FRP,” Journal of Composites for Construction, ASCE, V. 4, No. 4, 2000, pp. 198-205. doi: 10.1061/(ASCE)1090-0268(2000)4:4(198)
22. Chen, J. F., and Teng, T. G., “Shear Capacity of FRP Strengthened RC Beams: FRP Debonding,” Construction and Building Materials, V. 17, No. 1, 2003, pp. 27-41. doi: 10.1016/S0950-0618(02)00091-0
23. Bae, S. W., and Belarbi, A., “Behavior of Various Anchorage Systems Used for Shear Strengthening of Concrete Structures with Externally Bonded FRP Sheets,” Journal of Bridge Engineering, ASCE, V. 18, No. 9, 2013, pp. 837-847. doi: 10.1061/(ASCE)BE.1943-5592.0000420
24. Vecchio, F. J., and Collins, M. P., “The Modified Compression-Field Theory for Reinforced Concrete Elements Subjected to Shear,” ACI Journal Proceedings, V. 83, No. 2, Mar.-Apr. 1986, pp. 219-231.