Journal of the Architectural Institute of Korea (대한건축학회논문집)

Architectural Institute of Korea (대한건축학회)
권호 표지
DOI QR코드

DOI QR Code

Evaluating Shear Strength Equations for FRP-Strengthened Reinforced Concrete Beams

FRP로 전단보강된 철근콘크리트 보의 전단강도 식의 평가

  • Seo, Soo-Yeon (Dept. of Architectural Engineering, Korea National University of Transportation) ;
  • Lee, Seong-Kyeong (Dept. of Architectural Engineering, Korea National University of Transportation) ;
  • Jeong, Yeon-Su (Dept. of Architectural Engineering, Korea National University of Transportation) ;
  • Kim, Min (Dept. of Architectural Engineering, Korea National University of Transportation)
  • 서수연 (한국교통대학교 건축공학과) ;
  • 이성경 (한국교통대학교 건축공학과) ;
  • 정연수 (한국교통대학교 건축공학과) ;
  • 김민 (한국교통대학교 건축공학과)
  • Received : 2024.01.06
  • Accepted : 2024.06.21
  • Published : 2024.07.30
⟨ Previous Next ⟩

Abstract

This study aims to evaluate equations for shear strength in Reinforced Concrete (RC) beams strengthened with fiber reinforced polymer (FRP). A total of 79 experimental results from previous researchers were collected and classified by strengthening method. The existing equations were then evaluated based on these results. The shear strength calculation formulas considered include those by Nanni and Dias for Near Surface Mounted (NSM) reinforcement using FRP rods, and those by ACI and FIB for lateral confinement using FRP sheets. The analysis revealed that for U-wrap lateral confining reinforcement, neither the ACI nor the FIB calculation formulas could safely predict the strength after shear strengthening. For full-wrap lateral reinforcement, the critical effective strain of 0.004 for FRP, as defined by ACI, appears to be underestimated compared to experimental results. In the case of NSM strengthening, Dias calculates the effective strain through an equation, while Nanni uses an experimentally determined average value of 0.0059. The significant difference in the experiment/calculation ratio for both indicates a need for further research.

Keywords

Acknowledgement

본 연구는 2022년도 과학기술정보통신부 기초연구실지원사업 (No.2021R1A4A2001964)과 기초연구지원사업 (No.2022R1A2C2004460)의 지원을 받아 수행된 결과임.

References

  1. ACI Committee 440 (2017). Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures, American Concrete Institute.
  2. Akkaya, H. C., Aydemir, C., & Arslan, G. (2022). An experimental research on reinforced concrete deep beams fully wrapped with fiber reinforced polymers against shear. Case Studies in Construction Materials, 17, e01198.
  3. Barros, J. A. O., & Dias, S. J. E. (2006). Near surface mounted CFRP laminates for shear strengthening of concrete beams. Cement and Concrete Composites, 28(3), 276-292.
  4. Barros, J. A. O., & Dias, S. J. E. (2010). Performance of reinforced concrete T beams strengthened in shear with NSM CFRP laminates. Engineering Structures, 32(2), 373-384.
  5. Choi, J. H., Kim, M. S., Kim, H. C., & Lee, Y. H. (2013). Evaluation of Shear Strength of Concrete Beams Reinforced with FRP Plates. Journal of The Architectural Institute of Korea Structure & Construction, 29(6), 13-20.
  6. Dias, S. J. E., & Barros, J. A. O. (2013). Shear strengthening of RC beams with NSM CFRP laminates: Experimental research and analytical formulation. Composite Structures, 99. 477-490.
  7. fib-Bulletin 14. (2001). Externally bonded FRP reinforcement for RC structures. Technical report by Task Group 9.3 FRP (Fiber reinforced polymer) reinforce-ment for concrete structures. Federation Internationale du Beton-fib. 130.
  8. Leung, C. K. Y., Chen, Z., Lee, S., Ng, M., Xu, M., & Tang, J. (2007). Effect of Size on the Failure of Geometrically Similar Concrete Beams Strengthened in Shear with FRP Strips. Journal of Composites for Construction, 11(5), 487-496.
  9. Lim, D. H. (2020). An Experimental Study on the Failure Behavior of Reinforced Concrete Columns Strengthened with NSM and EBR CFRP Strips. Journal of the Korea Concrete Institute, 32(1), 45-51.
  10. Lim, D. H., & Kwon, Y. S. (2009). An Experimental Study on the Shear Behavior of RC Beams Strengthened with Near Surface Mounted and Externally Bonded CFRP Strips. Journal of the Korea Concrete Institute, 21(3), 337-345.
  11. Li, W., & Leung, C. K. Y. (2016). Shear Span-Depth Ratio Effect on Behavior of RC Beam Shear Strengthened with Full-Wrapping FRP Strip. Journal of Composites for Construction, 20(3), 04015067.
  12. Nanni, A., Ludovico, M., & Parretti, R. (2003). Shear Strengthening of a PC Bridge Girder with NSM CFRP Rectangular Bars. Advances in Structural Engineering, 7(4):297-309.
  13. Raj, S. D., & Surumi, R. S. (2012). Shear Strengthening of Reinforced Concrete Beams using Near Surface Mounted Glass Fibre Reinforced Polymer. Asian Journal of Civil Engineering (Building and Housing), 13(5), 679-690.
  14. Rizzo, A., & Lolenzis, L. D. (2007). Behavior and capacity of RC beams strengthened in shear with NSM FRP reinforcement. Construction and Building Materials, 23, 1555-1567.
  15. Seo, S. Y. (2012). Bond Strength of Near Surface-Mounted FRP Plate in RC Member, Journal of the Korea Concrete Institute, 24(4), 415-422.
  16. Seo, S. Y. (2014). Analysis on the Interfacial Bond-Slip Relationship between Near Surface-Mounted FRP Plate and Concrete, Journal of the Korea Concrete Institute, 26(1), 79-86.
  17. Seo, S. Y. (2016). Effect of Shear Key and Edge Length of Near Surface-Mounted FRP Plate in Concrete, Journal of the Korea Institute for Structural Maintenance and Inspection, 20(1), 41-47.
  18. Seo, S. Y., Choi, K. B., & Kwon, Y. S. (2012). Retrofit Capacity of Near-Surface-Mounted RC Beam by using FRP Plate. Journal of the Korea Institute for Structural Maintenance and Inspection, 16(1), 18-26.
  19. Seo, S. Y., Choi, K. B., Kwon, Y. S., & Lee, K. S. (2016a). Flexural Strength of RC Beam Strengthened by Partially De-bonded Near-Surface-Mounted FRP Strip. International Journal of Concrete Structures and Materials, Korea Concrete Institute, 10(2), 149-161.
  20. Seo, S. Y., Feo, L., & Hui, D. (2013). Bond Strength of Near-Surface-Mounted FRP Plate for Retrofit of Concrete Structures", Composite Structures. 95, 719-727.
  21. Seo, S. Y., & Kim, M. S. (2013) Bond Strength of Near Surface-Mounted FRP Plate in Concrete Corresponding to Space and Bond Length, Journal of the Korea Concrete Institute, 25(1), 37-43.
  22. Seo, S. Y., Lee, M. S., & Feo, L. (2016b). Flexural Analysis of RC Beam Strengthened by Partially De-bonded NSM FRP Strip. Composite Part B, 101(15), 21-30.
  23. Seo, S. Y., Oh, J. G., & Choi, K. B. (2011a). Bond Capacity of Concrete Member Strengthened by Various Methods Using FRP Plate. Journal of the Architectural Institute of Korea, 27(8), 55-63.
  24. Seo, S. Y., Tran, H. V., Kim, K. S., Yun, H. D., & Lee, G. C. (2023). Long-term Behavior of Reinforced Concrete Beams Flexurally Strengthened with FRP Strip. Journal of the Architectural Institute of Korea, 39(3), 231-238.
  25. Seo, S. Y., Yoon, S. J., Kwon, Y. S., & Choi, K. B. (2011b). Bond Behavior between Near-Surface-Mounted Fiber Reinforced Polymer Plates and Concrete in Structural Strengthening. Journal of the Korea Concrete Institute, 23(5), 675-682.