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Experimental Study on Effect of Confinement Details for Lap Splice of Headed Deformed Reinforcing Bars in Grade SD400 and SD500

구속상세가 SD400 및 SD500 확대머리 이형철근의 겹침이음에 미치는 영향에 관한 실험적 연구

  • 김승훈 (한밭대학교 건축공학과)
  • Received : 2014.12.26
  • Accepted : 2015.01.08
  • Published : 2015.01.30

Abstract

KCI 2012 and ACI318-11 contains development length provisions for the use of headed deformed bars in tension and does not allow their tension lap splices. In ACI318-11, the confinement factor, such as transverse reinforcement factor, is not used to calculate the development length of headed bars. The purpose of this experimental study is to evaluate the effect of confinement details to the lap splice performance of headed deformed reinforcing bars in grade SD400 and SD500. The confinement details are stirrups and tie-down bars in lap zone. Test results showed that specimens with only stirrups had the brittle failure and could not increase lap strengths, and that specimens with composite confinements by stirrups and tie-down bars had the flexural strengths over than nominal flexural strengths. Stirrups with tie-down bars can have an effect on improvement in lap splice of headed bars in grade SD400 and SD500.

KCI 2012와 ACI318-11에서 확대머리 이형철근에 대한 정착길이 산정식을 제시하고 있지만 확대머리 이형철근을 이용한 겹침이음상세에 대한 규정은 없다. 또한, 정착길이 산정에 있어서 횡보강근 효과는 고려하지 않고 있다. 본연구에서는 400MPa과 500MPa 설계기준항복강도를 가지는 확대머리 이형철근에 대하여 겹침이음구간에 대한 구속상세를 평가하기 위하여 겹침이음실험을 실시하였다. 겹침이음 구간내 적용되는 구속상세는 스터럽과 Tie-down 철근이다. 실험결과, 스터럽만으로 보강된 실험체들에서 겹침이음강도 증가에 큰 영향이 없어 취성적인 파괴를 나타낸 반면에, 스터럽과 Tie-down 철근으로 보강된 실험체들은 공칭휨강도 이상의 실험휨강도와 휨거동을 나타내었다. 따라서 스터럽과 Tie-down 철근 상세는 400MPa과 500MPa의 확대머리 이형철근에 대한 겹침이음 성능향상에 기여할 수 있는 것으로 사료된다.

Keywords

References

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  2. Experimental Study on the Flexural Strength of Joints of Concrete Members for Details of Headed Deformed Reinforcing Bars vol.19, pp.5, 2015, https://doi.org/10.9798/kosham.2019.19.5.199
  3. SFRC 부재에 수직 배근된 고강도 확대머리철근의 정착강도 vol.24, pp.1, 2020, https://doi.org/10.11112/jksmi.2020.24.1.148