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Behaviour of Lightweight Concrete Slab Reinforced with GFRP Bars under Concentrated Load

집중하중을 받는 GFRP 보강근 경량콘크리트 슬래브의 거동

  • 손병락 ((주) 선익) ;
  • 김충호 (경성대학교 건설환경도시공학부 토목공학전공) ;
  • 장희석 (부경대학교 토목공학과)
  • Received : 2015.02.27
  • Accepted : 2015.04.17
  • Published : 2015.07.30

Abstract

This paper is a preliminary study to apply the lightweight concrete slabs reinforced with GFRP (glass fiber reinforced polymer) bars to the bridge deck slabs or some other concrete structures. So, some different behaviors between the conventional steel reinforced concrete slab and the lightweight concrete slab reinforced with GFRP bars were investigated. For this purpose, a number of slabs were constructed and then the three point bending test and numerical analysis for these slabs were performed. The flexural test results showed that the lightweight concrete slabs reinforced with GFRP bars were failed by the shear failure due to the over-reinforced design. The weight and failure load of the GFRP bar reinforced lightweight concrete slabs were 72% and 58% of the steel reinforced concrete slab with the same dimensions, respectively. Results of the numerical analysis for these slabs using a commercial program, midas FEA, showed that the load-deflection curve could be simulated well until the shear failure of the slabs, but the applied loads and the deflections continuously increased even beyond the shear failure loads.

본 연구는 경량콘크리트와 GFRP 보강근을 휨보강근으로 사용하여 제작되는 GFRP 보강근 경량콘크리트 슬래브를 교량 슬래브 등에 활용해보기 위한 사전 연구로서, 기존의 철근 콘크리트 슬래브와 GFRP 보강근 경량콘크리트 슬래브의 휨 거동 차이점 분석에 초점을 두었다. 이를 위하여 일련의 슬래브 실험체들을 제작하고 3점 휨 실험 및 수치해석을 행하였다. 실험 결과, GFRP 보강근 경량콘크리트 슬래브 실험체는 GFRP 보강근의 과다보강으로 인하여 실험체 하부에 발생된 초기균열이 하중 재하면의 콘크리트 압축부까지 연결되면서 전단파괴되는 경향을 보였다. 그리고 철근 콘크리트로 제작된 슬래브 실험체에 비하여 무게는 72%이었으며 휨 실험에서의 파괴하중은 58%인 것으로 나타났다. 한편, midas FEA를 이용하여 행한 수치해석 과정은 실험에서 나타난 전단파괴 하중까지 잘 모사하였다. 그러나 GFRP 보강근의 인장강도 대신 탄성계수가 입력값으로 요구됨에 따라 가력되는 하중과 처짐은 실험에서 나타난 전단파괴 이후에도 계속하여 증가하는 경향을 보였다.

Keywords

References

  1. ACI 440.IR-06 (2006), Guide for the Design and Construction of Concrete Reinforced with FRP bars, American Concrete Institute, Farmington Hills, Michigan.
  2. Ahmed, E. A., El-Salakawy, E. F., and Benmocrane, B. (2010), Shear Performance of RC Bridge Girders Reinforced with Carbon FRP Stirrups, Journal of Bridge Engineering, 15(1), 44-54. https://doi.org/10.1061/(ASCE)BE.1943-5592.0000035
  3. CSA standards S806-12 (2012), Design and construction of building structures with fibre-reinforced polymers, Canadian Standards Association.
  4. El-sayed, A. K., El-Salakawy, E. F., and Benomkrane, B. (2006), Shear strength of FRP reinforced concrete beam without transverse reinforcement, ACI Structural Journal, 103(2), 235-243.
  5. Hassan, T., Abdelrahman, A., Tadros, G., and Rizkalla, S. (2000), Fiber reinforced polymer reinforcing bars for bridge decks, Can. J. Civ. Eng, 27, 839-849. https://doi.org/10.1139/l99-098
  6. Jeon, S. H., Shon, B. L., Kim, C. H., and Jang, H. S. (2012), A Fundamental Study for the Behavior of Lightweight Aggregate Concrete Slab Reinforced with GFRP Bar, Journal of the Korea Institute for Structural Maintenance and Inspection, 16(3), 99-108. https://doi.org/10.11112/jksmi.2012.16.3.099
  7. Kim, C. H. and Jang, H. S. (2014), Concrete Shear Strength of Normal and Lightweight Concrete Beams Reinforced with FRP Bars, Journal of Composites for Construction, 18(2), 04013038. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000440
  8. Kwak, Y. K. and Jang, I. Y. (1998), Research Trends of Structural Lightweight Concrete, Journal of the Korea Concrete Institute, 10(4), 5-15.
  9. Lee, J. H., Yang, J. M., and Yoon, Y. S. (2007), Application of Concentrated FRP Bars to Enhance the Capacity of Two-Way Slabs, Journal of the Korea Concrete Institute, 19(6), 727-734. https://doi.org/10.4334/JKCI.2007.19.6.727
  10. Malvar, L. J., Cox, J. V., and Cochran, K. B. (2003), Bond between carbon fiber reinforced polymer bars and concrete. I: Experimental study, Journal of composites for construction, 7(2), 154-163. https://doi.org/10.1061/(ASCE)1090-0268(2003)7:2(154)
  11. midas FEA, Technical Paper ; Crack Analysis of PSC Box, MIDAS.
  12. Pantelides, C. P., Besser, B. T., and Liu, R. (2012), One-Way Shear Behavior of Lightweight Concrete Panels Reinforced with GFRP Bars, Journal of Composites for Construction, 16(1), 2-9. https://doi.org/10.1061/(ASCE)CC.1943-5614.0000240
  13. Sherif El-Gamal, Ehab El-Salakawy, and Brahim Benmokrane (2007), Influence of Reinforcement on the Behavior of Concrete Bridge Deck Slabs Reinforced with FRP Bars, Journal of Composites for Construction, 11(5), 449-458. https://doi.org/10.1061/(ASCE)1090-0268(2007)11:5(449)
  14. Shin, S. W. and Choi, M. S. (1998), Application and Prospection of Structural Lightweight Concrete, Journal of the Korea Concrete Institute, 10(4), 16-26.
  15. Son, B. L., Kim, M. S., Kim, C. H., and Jang, H. S. (2013), Bond Characteristic between Lightweight Concrete and GFRP Bar, Journal of the Korea Institute for Structural Maintenance and Inspection, 17(6), 112-121. https://doi.org/10.11112/jksmi.2013.17.6.112
  16. TNO DIANA (2005), DIANA, User's manual, Material Library, Release 9.
  17. You, Y. J., Park, Y. H., and Park, J. S. (2008), Service and Ultimate Load Behavior of Bridge Deck Reinforced with GFRP Rebars, Journal of The Korean Society of Civil Engineers, 28(5A), 719-727.