Post-Tensioned Concrete Beams Strengthened in Shear Using Fiber-Reinforced Polymer Laminates and Patch Anchors
Publication: Journal of Composites for Construction
Volume 24, Issue 2
Abstract
Strengthening concrete bridges using fiber-reinforced polymers (FRPs) in flexure, shear, and torsion is limited by the occurrence of premature FRP debonding which often controls the degree of strengthening possible using this approach. To address this issue, anchorage systems have been developed in recent years to mitigate FRP debonding failure modes with the objective of achieving higher levels of strengthening using less material. Of the many types of anchorage systems researched to date, joint level tests have revealed that bidirectional fiber patches placed at the ends of the FRP laminates can significantly delay the occurrence of FRP debonding. This study presents the first experimental application where patch anchors are evaluated in post-tensioned concrete beams strengthened in shear using FRP laminates. Three specimens were tested including an unstrengthened control beam and strengthened beams with and without anchors. The anchors were proven to significantly improve the shear capacity of the member and increase the FRP laminate strain utilization prior to failure. The experimental results were verified against predictions provided by the modified compression field theory (MCFT) and the ACI 318. A semiempirical model (SE model) was proposed to predict the shear contributions provided by the anchored FRP laminates.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
All data, models, and code generated or used during the study appear in the published article.
Acknowledgments
The support of FYFE Asia Ltd. is gratefully acknowledged for sponsoring this project and supplying all the FRP and epoxy material used.
References
ACI (American Concrete Institute). 2014. Building code requirements for structural concrete and commentary. ACI 318. Farmington Hills, MI: ACI.
ACI (American Concrete Institute). 2017. Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI 440.2. Farmington Hills, MI: ACI.
Alam, M. A., A. S. Alshaikhly, and K. N. Mustapha. 2016. “An experimental study on the debonding of steel and FRP Strips externally bonded to concrete in the presence of embedded shear connectors.” Arabian J. Sci. Eng. 41 (10): 4171–4186. https://doi.org/10.1007/s13369-016-2123-5.
Al-Mahaidi, R., and R. Kalfat. 2011a. “Investigation into FRP laminate anchorage systems utilising bidirectional fabric wrap.” Compos. Struct. 93 (4): 1265–1274. https://doi.org/10.1016/j.compstruct.2010.10.012.
Al-Mahaidi, R., and R. Kalfat. 2011b. “Investigation into FRP plate end anchorage utilising uni-directional fabric wrap.” Compos. Struct. 93 (2): 821–830. https://doi.org/10.1016/j.compstruct.2010.07.012.
AS (Standards Australia). 2018. Concrete structures. AS 3600. Sydney, Australia: AS.
AS (Standards Australia). 2014. Methods of testing concrete—Determination of the compressive strength of concrete specimens. AS 1012.9. Sydney, Australia: AS.
AS (Standards Australia). 2017. Bridge design Part 8: Rehabilitation and strengthening of existing bridges. AS 5100.8. Sydney, Australia: AS.
ASTM. 2017. Standard test method for tensile properties of polymer matrix composite materials. ASTM D3039. West Conshohocken, PA: ASTM.
Baggio, D., K. Soudki, and M. Noël. 2014. “Strengthening of shear critical RC beams with various FRP systems.” Supplement, Constr. Build. Mater. 66 (SC): 634–644. https://doi.org/10.1016/j.conbuildmat.2014.05.097.
Bentz, E. C., F. J. Vecchio, and M. P. Collins. 2006. “Simplified modified compression field theory for calculating shear strength of reinforced concrete elements.” ACI Mater. J. 103 (4): 614–624.
CSA (Canadian Standards Association). 2014. Design of concrete structures. CSA A23.3. Mississauga, ON: CSA.
Eshwar, N., A. Nanni, and T. Ibell. 2008. “Performance of two anchor systems of externally bonded fiber-reinforced polymer laminates.” ACI Mater. J. 105 (1): 72–80.
Ingram, L. 2014. “Incorporating ACI440.2r into AS5100.5 for FRP strengthening via M80 upgrade project case study.” In Proc., 9th on Austroads Bridge Conf. Washington, DC: Transportation Research Board.
ISO. 2009. Plastics—Determination of tensile properties—Part 5: Test conditions for unidirectional fiber-reinforced plastic composites. ISO 527-5. Geneva: ISO.
JCI (Japan Concrete Institute). 2003. “Technical report of technical committee on retrofit technology.” In Proc., Int. Symp. on Latest Achievements of Technology and Research on Retrofitting Concrete Structures, 4–42. Kyoto, Japan: JCI.
Kalfat, R., and R. Al-Mahaidi. 2010. “Investigation into bond behaviour of a new FRP anchorage system for concrete utilising a mechanically strengthened substrate.” Compos. Struct. 92 (11): 2738–2746. https://doi.org/10.1016/j.compstruct.2010.04.004.
Kalfat, R., and R. Al-Mahaidi. 2014a. “A prediction model for bidirectional fiber patch anchors used to enhance the performance of FRP materials bonded to concrete.” Compos. Struct. 117 (Nov): 51–58. https://doi.org/10.1016/j.compstruct.2014.05.034.
Kalfat, R., and R. Al-Mahaidi. 2014b. “Experimental investigation into the size effect of bidirectional fiber patch anchors in strengthening of concrete structures.” Compos. Struct. 112 (Jun): 134–145. https://doi.org/10.1016/j.compstruct.2014.02.011.
Kalfat, R., and R. Al-Mahaidi. 2015. “Development of a hybrid anchor to improve the bond performance of multiple plies of FRP laminates bonded to concrete.” Constr. Build. Mater. 94 (Sep): 280–289. https://doi.org/10.1016/j.conbuildmat.2015.07.013.
Kalfat, R., and R. Al-Mahaidi. 2016a. “Improvement of FRP-to-concrete bond performance using bidirectional fiber patch anchors combined with FRP spike anchors.” Compos. Struct. 155 (Nov): 89–98. https://doi.org/10.1016/j.compstruct.2016.08.010.
Kalfat, R., and R. Al-Mahaidi. 2016b. “Mitigation of premature failure of FRP bonded to concrete using mechanical substrate strengthening and FRP spike anchors.” Composites Part B 94 (Jun): 209–217. https://doi.org/10.1016/j.compositesb.2016.03.062.
Kalfat, R., R. Al-Mahaidi, and S. T. Smith. 2013. “Anchorage devices used to improve the performance of reinforced concrete beams retrofitted with FRP composites: A state-of-the-art review.” J. Compos. Constr. 17 (1): 14–33. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000276.
Kalfat, R., R. Al-Mahaidi, and G. Williams. 2011. “Investigation of efficient anchorage systems for shear and torsional retrofitting of box girder bridges.” In Proc., 10th Int. Symp. on Fiber-Reinforced Polymer Reinforcement for Concrete Structures. Tampa, FL: American Concrete Institute.
Kalfat, R., J. Gadd, R. Al-Mahaidi, and S. T. Smith. 2018. “An efficiency framework for anchorage devices used to enhance the performance of FRP strengthened RC members.” Constr. Build. Mater. 191 (Dec): 354–375. https://doi.org/10.1016/j.conbuildmat.2018.10.022.
Khalifa, A., T. Alkhrdaji, A. Nanni, and S. Lansburg. 1999. “Anchorage of surface mounted FRP reinforcement.” Concr. Int.: Des. Constr. 21 (10): 49–54.
Khalifa, A., W. J. Gold, A. Nanni, and M. I. Abdel Aziz. 1998. “Contribution of externally bonded FRP to shear capacity of flexural members.” J. Compos. Constr. 2 (4): 195–202. https://doi.org/10.1061/(ASCE)1090-0268(1998)2:4(195).
Maeda, T., Y. Asano, Y. Sato, T. Ueda, and Y. Kakuta. 1997. “A study on bond mechanism of carbon fiber sheet.” In Vol. 1 of Proc., 3rd Int. Symp. Non-Metallic (FRP) Reinforcement for Concrete Structure, 279–285. Sapporo, Japan: Japan Concrete Institute.
Ozden, S., H. M. Atalay, E. Akpinar, H. Erdogan, and Y. Z. Vulaş. 2014. “Shear strengthening of reinforced concrete T-beams with fully or partially bonded fiber-reinforced polymer composites.” Struct. Concr. 15 (2): 229–239. https://doi.org/10.1002/suco.201300031.
Raghu, A., M. Mettemeyer, J. J. Myers, and A. Nanni. 2000. “An assessment of in-situ FRP shear and flexural strengthening of reinforced concrete joists.” In Advanced technology in structural engineering, ASCE structures congress, edited by M. Elgaaly. Reston, VA: Structural Engineering Institute of ASCE.
Response. 2000. “Response-2000 reinforced concrete sectional analysis.” Accessed August 25, 2018. www.ecf.utoronto.ca/∼bentz/r2k.htm.
Sato, Y., T. Ueda, Y. Kakuta, and S. Ono. 1997. “Ultimate shear capacity of reinforced concrete beams with carbon fiber sheet.” In Proc., 3rd Int. Symp. Non-Metallic Reinforcement for Concrete Structures, 499–506. Sapporo, Japan: Japan Concrete Institute.
Smith, S. T. 2009. “FRP anchors: Recent advances in research and understanding.” In Proc., 2nd Asia-Pacific Conf. on FRP in Structures, Asia-Pacific Conf. on FRP in Structures, 35–44. East Lismore, NSW, Australia: Southern Cross Univ.
Smith, S. T. 2010. “Strengthening of concrete, metallic and timber construction materials with FRP composites.” In Proc., 5th Int. Conf. on FRP Composites in Civil Engineering, 13–19. East Lismore, NSW, Australia: Southern Cross Univ.
Tanaka, T. 1996. “Shear resisting mechanism of reinforced concrete beams with CFS as shear reinforcement.” Ph.D. thesis, Faculty of Engineering, Hokkaido Univ.
Tyfo BCC. 2018. Datasheet for Tyfo BCC composite using Tyfo S Epoxy. San Diego: Aegion Fyfe Co. LLC.
Van Gemert, D. 1980. “Force transfer in epoxy bonded steel/concrete joints.” Int. J. Adhes. Adhes. 1 (2): 67–72. https://doi.org/10.1016/0143-7496(80)90060-3.
Vecchio, F. J., and M. P. Collins. 1986. “The modified compression-field theory for reinforced concrete elements subjected to shear.” ACI J. Proc. 83 (2): 219.
Williams, G., R. Al-Mahaidi, and R. Kalfat. 2011. “The West gate bridge: Strengthening of a 20th century bridge for 21st century loading.” ACI Spec. Publ. 275: 1–18.
Yoshizawa, H., and Z. Wu. 1997. “Analysis of debonding fracture properties of CFS strengthened member subject to tension.” In Proc., 3rd Int. Symp. Non-metallic (FRP) Reinforcement for Concrete Structures, 287–294. Sapporo, Japan: Japan Concrete Institute.
Yuksel, E., A. Ilki, G. Erol, C. Demir, and H. F. Karadogan. 2006. “Advances in earthquake engineering for urban risk reduction.” In NATO science series book, edited by T. Wasti and G. Ozcebe. New York: Springer.
Zhang, H. W., S. T. Smith, and S. J. Kim. 2010. “Optimisation of carbon and glass FRP anchor design.” Constr. Build. Mater. 32 (Jul): 1–12. https://doi.org/10.1016/j.conbuildmat.2010.11.100.
Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 24 • Issue 2 • April 2020
Copyright
©2019 American Society of Civil Engineers.
History
Received: Jun 4, 2018
Accepted: Jun 4, 2019
Published online: Dec 30, 2019
Published in print: Apr 1, 2020
Discussion open until: May 30, 2020
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.