Journal of Urban Science (도시과학)

Urban Science Institute (인천대학교 도시과학연구원)
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Anchorage performance tests of SD700 hooked bar and headed bar with a anchorage length of 20db

20db 정착길이를 가지는 SD700 갈고리철근과 확대머리철근의 정착성능 실험

  • 김호영 (영남대학교 건설시스템공학과) ;
  • 심혜정 (인천대학교 도시과학대학 건축학과)
  • Received : 2018.11.30
  • Accepted : 2018.12.30
  • Published : 2018.12.30
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Abstract

With the increase of the skyscraper center, the development of large-diameter and high-strength reinforcing bars is being carried out to solve the dense reinforcement. In case of the steel reinforced concrete with a small cross section such as beam-column joints, the development length becomes short when straight bars are used. Therefore, it is possible to solve the problem that the development length becomes short by using the bearing strength of the hooked bar and headed bar. In this study, the exterior beam-column joint test of SD700 hooked bar and headed bar with anchorage length of 20db was conducted to extend the development length limitation of hooked bar and headed bar. As a result of the evaluation of the anchorage strength using the design equation by KCI, the average of the [measured value]/[predicted value] ratio was 1.31 for the hooked reinforcing bars. In the case of headed bars, the average of the [measured value]/[predicted value] ratio was 1.12. In addition, in order to compare the anchorage performance of the hooked bar and the headed bar, the measured values were divided by the square root of the compressive strength of the concrete to compare the anchorage strength. Under the same conditions, the anchorage strength of headed bars was 8.5% higher than the hooked bars.

Keywords

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Figure 1. Marques and Jirsa(1975)의 갈고리철근 외부 보-기둥 접합부 실험

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Figure 2. Chun et al.(2017)의 확대머리철근 외부 보-기둥 접합부 실험

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Figure 3. 실험 가력도

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Figure 4. 실험체 상세

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Figure 5. SD700 철근인장시험 stress-strain 곡선

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Figure 6. 측면파열파괴양상

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Figure 7. 콘크리트구조기준에 따른 예측값에 대한 실험값

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Figure 7. 갈고리철근과 확대머리철근의 정착강도 비교

Table 1. 실험체 목록

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Table 2. 콘크리트 재료시험 결과

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Table 3. 철근인장강도시험 결과

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Table 4. 외부 보-기둥 접합부 정착강도 실험결과

TSGHB4_2018_v7n2_21_t0004.png 이미지

References

  1. ACI Committee 352R (2002), "Recommendations for Design of Beam-Column Connections in Monolithic Reinforced Concrete Structures", ACI, Farmington Hills, Mich., USA, 2002, 38
  2. ASTM A615 (2016), "Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement", ASTM, West Conshohocken, PA, 8.
  3. ASTM A970 (2015), "Standard Specification for Headed Steel Bars for Concrete Reinforcement", ASTM, West Conshohocken, PA., 9 pp.
  4. Bae, M.-S., Chun, S.-C., and Kim, M.-G., (2016), "Behavior of 550 MPa 43 mm Hooked Bars Embedded in Beam-Column Joints", Journal of the Korea Concrete Institute, 28(5), 611-620 (In Korean) https://doi.org/10.4334/JKCI.2016.28.5.611
  5. Bashandy T. R., (1996), "Application of Headed Bars in Concrete Members", Ph.D, The University of Texas at Austin. 303pp.
  6. Chun, S. C., (2015), "Lap Splice Tests Using High-Strength Headed Bars of 550MPa (80ksi)", Yield Strength ACI Structural Journal, 112(6). 679-688.
  7. Chun, S. C., Bae, M. S., and Lee, B. S., (2017), " Side-Face Blowout Strength of 43 and 57 mm(No. 14 and No. 18) Hooked Bars in Beam-Column Joints", ACI Structural Journal, 114(5), 1227-1238 https://doi.org/10.14359/51700804
  8. Chun, S. C., Choi, C. S., Jung, H. S., (2017) Side-Face Blowout Failure of Large-Diameter High-Strength Headed Bars in Beam-Column Joints. ACI Structural Journal. 114(1). 1-12.
  9. Korea Concrete Institute (KCI) (2012), "Concrete Design Code and Commentary" Kimoondang Publishing Company, Seoul, 2012, 599 (In Korean)
  10. KS D 3504: (2016), "Steel Bars for Concrete Reinforcement", Korean Agency for Technology and Standards, 2016, 31
  11. Marques, J. L. G. and Jirsa, J. O., (1975), "A Study of Hooked Bar Anchorages in Beam-Column Joints", ACI Journal, Proceedings, 72(5), 198-209.