DOI QR코드

DOI QR Code

An Evaluation of Lap Splice Length of Epoxy Coated Reinforcements Using Beam-End Test

보-단부 시험을 이용한 에폭시 도막 철근의 겹침 이음길이 평가

  • Received : 2020.02.26
  • Accepted : 2020.04.03
  • Published : 2020.06.30

Abstract

The application of epoxy coated reinforcements is increased as a means to prevent a corrosion of reinforcements embedded in reinforced concrete structures, However, epoxy coating may reduce the bond capacity between concrete and reinforcement, which results a longer development length and lap splice length. This paper aims to the possibility of modification in lap splice length from reduction of basic development length which was confirmed using a direct pull out test. Total 36 beam specimens were tested to compare the lap splice properties of normal and epoxy coated reinforcements with beam-end test for various lap lengths and diameters of reinforcements. According to the results on failure modes, deformations, and crack widths of this experiments, the modification factor of 1.2 should be used, though the direct bond capacity is assured through direct pull out test.

철근 부식으로 인한 철근 콘크리트 구조물의 내구성능 저하를 방지하는 방법 중 하나인 에폭시 도막 철근의 사용이 증가하고 있으나, 에폭시 도막으로 인한 콘크리트와 철근의 부착성능 부족으로 정착길이 및 겹침이음길이를 증가시켜야하는 것이 문제가 된다. 이 논문은 에폭시 도막 철근의 부착성능을 개선하여 직접인발시험에서 확인한 기본정착길이의 감소 가능성을 실제 휨부재의 이음길이 산정에 반영할 수 있는지를 확인하기 위하여 수행한 실험연구를 정리한 것이다. 휨부재에서 일반철근과 에폭시 도막 철근의 겹침이음 특성을 비교하기 위하여 철근지름 및 겹침이음길이를 변수로 하여 36개의 시험체로 보-단부 실험을 통해 겹침 이음 성능평가를 하였다. 실험결과에 의하면 현행설계기준에 따라 이음길이에 보정계수 1.2를 사용한 에폭시 도막 철근 부착강도와 일반철근 부착강도를 비교한 결과 파괴 양상, 처짐특성 및 균열폭 등을 고려할 때 현행 설계기준에 따른 보정계수의 필요성을 확인하였다.

Keywords

References

  1. ACI Committee 318 (2014). Building Code Requirements for Structural Concrete (ACI318-14).
  2. ACI Committee 408 (2003). Bond and Development of Straight Reinforcing Bars in Tension(408R-03), 31-32.
  3. CEN(2004). EuroCode 2, Design of Concrete Structures-General Rules and Rules for Buildings, 131-151.
  4. Choi, O.C. (1990). Bond of epoxy-coated reinforcing bars, Journal of the Architectural Institute of Korea, 10(2), 539-542. [In Korean]
  5. Choi, O.C., Kim, C.H., Shin, Y.S., Hong, G.S. (1994). Performance test of epoxy coated reinforcing bars: mechanical properties, Journal of the Korea Concrete Institute, 6(3), 173-179 [in Korean].
  6. EIG(2011). http://www.epoxyinterestgroup.org/resourcessearch
  7. fib (2010) fib Model Code for Concrete Structures, fib, Switzerland.
  8. Jung, K.O. (2003). Study on The Calculation of Lap Splices Length in High-Strength Concrete Flexural Members, Master's Thesis, Chonnam National University [In Korean].
  9. Kim J.S., Choi, D.H. (2018). A stress transfer length of pre-tensioned members using ultra high performance concrete, Journal of the Korean Recycled Construction Resources Institute, 6(4), 336-341 [In Korean]. https://doi.org/10.14190/JRCR.2018.6.4.336
  10. Kim J.S., Lee, S.H. (2017). Bond behaviors of epoxy coated reinforcements using direct pull-out test, Journal of the Korean Recycled Construction Resources Institute, 5(3), 298-304 [In Korean]. https://doi.org/10.14190/JRCR.2017.5.3.298
  11. Korean Concrete Institute (2017). Design Code for Concrete Structures, KCI [in Korean].
  12. Lee, K.Y., Kim, W., Lee, H.M. (2009). Tension lap splice length in high-strength concrete flexural members, Journal of the Korea Concrete Institute, 21(6), 753-761 [In Korean]. https://doi.org/10.4334/JKCI.2009.21.6.753
  13. Lee, S.H. (2018), Quality Assessment and Bond Characteristics of Epoxy Coated Reinforcements, Master's Thesis, Seokyeong University [In Korean].
  14. Ministry of Land, Infrastructure and Transport (MOLIT) (2016). Korean Highway Bridge Design Code(Limit State Design), MOLIT [In Korean].
  15. Shin, Y.S., Choi, O.C. (1997). Bond properties of epoxy coated bars in high strength concrete, Journal of the Architectural Institute of Korea, 13(6), 209-213 [In Korean].
  16. Treece, R.A., Jirsa, J.O. (1989). Bond strength of epoxy-coated reinforcing bars, ACI Materials Journal, 86(2), 167-174.