Journal of the Korea Concrete Institute (콘크리트학회논문집)

Korea Concrete Institute (한국콘크리트학회)
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Experimental Evaluation of the Punching Shear Strength with Lightweight Aggregate Concrete Slabs

경량골재 콘크리트 바닥판의 펀칭전단강도의 실험적 평가

  • Received : 2014.04.14
  • Accepted : 2014.06.05
  • Published : 2014.06.30
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Abstract

This paper investigates the punching shear strength of lightweight aggregate concrete (LWAC) slabs through a series of experimental study. Five full scale slabs were constructed using normal concrete and four different types of LWAC. Each lightweight aggregate (LWA) used in this study had different sources (clay, shale, or slate) and shapes (crushed or spherical shape). Based on the test results, the effect of the lightweight aggregates (LWA) on the punching shear behavior was investigated. From the test results, it was found that the punching shear failure surface of LWAC slab with spherical shape coarse aggregate was less inclined than that with crushed shape coarse aggregate, which resulted in an increase of the area of the shear failure surface. As a result, it leads to the increased punching shear strength of the slab. On the other hand, the failure surfaces of LWAC slab with crushed shape coarse aggregate and normal coarse aggregate were inclined similarly. Finally, the test results of this study were compared with the punching shear strength obtained from current design models, such as ACI and CEB-FIP, to examine the validation of current design model to predict the punching shear strength of the LWAC slab.

이 연구에서는 실험연구를 통하여 경량골재콘크리트 바닥판의 펀칭전단강도를 평가하였다. 일반콘크리트와 서로 다른 4 종류의 경량골재를 사용하여 총 5 개의 바닥판 실험체를 제작하였다. 이 연구에서 사용된 4 가지의 경량골재는 서로 원재료(점토, 셰일, 혹은 점판암) 및 형상 (원형 혹은 분쇄형)이 다르며, 이러한 서로 다른 경량 골재들이 바닥판의 펀칭전단강도에 미치는 영향을 실험 결과를 바탕으로 분석하였다. 실험 결과, 원형 경량골재로 만든 바닥판실험체의 펀칭전단파괴면은 일반콘크리트 실험체 및 파쇄된 경량골재 바닥판실험체보다 기울기가 낮았으며, 이로 인해 전단파괴면이 더 넓게 분포하였다. 이로 인해 펀칭 전단강도가 증가될 수 있었다. 반면에 파쇄된 경량골재의 경우 파괴면이 일반 콘크리트와 유사한 것으로 나타났다. 마지막으로 실험 결과를 현재 펀칭전단강도를 예측하는데 널리 쓰이는 국내기준과 ACI318-11 및 CEB-FIP 코드와 비교 분석하여 경량골재콘크리트 바닥판의 펀칭전단강도 예측의 유효성을 검증하였다.

Keywords

References

  1. Castrodale, R. W. and Harmon, K. S., "Recent Projects Using Lightweight and Specified Density Concrete for Precast Bridge Elements," The PCI-FHWA National Bridge Conference, Phoenix, USA, 2007, pp. 1-14.
  2. Castrodale, R. W. and Ries, J. P., "Use of Lightweight Concrete Decks for Accelerated Bridge Construction," the Proceedings of the 3rd Accelerated Bridge Construction Conference, San Diego, USA, 2005, pp. 1-6.
  3. Yun, T. S., Jeong, Y. J., Han, T. S., and Youm, K. S., "Evaluation of Thermal Conductivity for Thermally Insulated Concretes," Energy and Buildings, Vol. 61, 2013, pp. 125-132. https://doi.org/10.1016/j.enbuild.2013.01.043
  4. Yun, T. S., Jeong, Y. J., and Youm, K. S., "Effect of Surrogate Aggregates on the Thermal Conductivity of Concrete at Ambient and Elevated Temperatures," The Scientific World Journal, Vol. 2014, pp. 1-9.
  5. Kim, S. H., Jeon, H. K., Hwang, I. D., Seo, C. H., and Kim, S. H., "The Properties of Concrete with Lightweight Aggregate Impregnated by Phase Change Materia," Journal of the Korea Concrete Institute, Vol. 25, No. 3, 2013, pp. 331-338. https://doi.org/10.4334/JKCI.2013.25.3.331
  6. Fergestad, S. and Asa-Jakobsen, I. A., "Bridges Built with Lightweight Concrete in Norway," International Symposium on Lightweight Concrete Bridges, USA, 1996, pp. 1-26.
  7. Manzanarez, R., "The New Benicia-Martinez Bridge Project: A Lightweight Concrete Segmental Structure," International Symposium on Lightweight Concrete Bridges, USA, 1996, pp. 27-37.
  8. Dhir, K., Mays, R. G. C., and Chua, H. C., "Lightweight Structural Concrete with Aglite Aggregate: Mix Design and Properties," The International Journal of Cement Composites and Lightweight Concrete, Vol. 6, No. 4, 1984, pp. 249-261. https://doi.org/10.1016/0262-5075(84)90020-4
  9. Marzouk, H. and Hussein, A., "Experimental Investigation on the Behavior of High-Strength Concrete Slabs," ACI Structural Journal, Vol. 88, No. 6, 1991, pp. 701-713.
  10. Guandalini, S., Burdet, O. L., and Muttoni, A., "Punching Tests of Slabs with Low Reinforcement Ratios," ACI Structural Journal, Vol. 106, No. 1, 2009, pp. 87-95.
  11. ACI 318-11, Building Code Requirements for Structural Concrete, American Concrete Institute (ACI), Farmington Hills, Michigan, USA, 2011.
  12. CEB-FIP Model Code 2010, Bulletin D'Information, Lausanne, Switzerland, 2011.
  13. Elshafey, A. A., Rizk, E., Marzoukd, H., and Haddarac, M. R., "Prediction of Punching Shear Strength of Two-Way Slabs," Engineering Structures, Vol. 33, No. 5, 2011, pp. 1742-1753. https://doi.org/10.1016/j.engstruct.2011.02.013
  14. Choi, K., Taha, M., and Sherif, A., "Simplified Punching Shear Design Method for Slab-Column Connections using Fuzzy Learning," ACI Structural Journal, Vol. 104, No. 4, 2007, pp. 438-447.
  15. Theodorakopoulos, D. D. and Swamy, R. N., "Ultimate Punching Shear Strength Analysis of Slab-Column Connections," Cement & Concrete Composites, Vol. 24, No. 6, 2002, pp. 509-521. https://doi.org/10.1016/S0958-9465(01)00067-1
  16. Swamy, R. N. and Ali, S. A. R., "Punching Shear Behavior of Reinforced Slab-Column Connections Made with Steel Fiber Concrete," ACI Structural Journal, Vol. 79, No. 6, 1982, pp. 392-406.
  17. Cho, S. K., Kwark, J. W., Lee, J. M., and Moon, D. J., "Punching Shear Behavior of High-strength Lightweight Concrete Slab Under Concentrated Load," Journal of the Korean Society of Civil Engineering, Vol. 26, No. 11, 2006, pp. 219-228
  18. Marzouk, H., Osman, M., and Helmy, S., "Behavior of High-Strength Lightweight Aggregate Concrete Slabs under Column Load and Unbalanced Moment," ACI Structural Journal, Vol. 97, No. 6, 2000, pp. 860-866.
  19. Chung, S. Y., Han, T. S., Yun, T. S., and Youm, K. S., "Evaluation of the Anisotropy of the Void Distribution and the Stiffness of Lightweight Aggregates Using CT imaging," Construction and Building Materials, Vol. 48, 2013, pp. 998-1008. https://doi.org/10.1016/j.conbuildmat.2013.07.082
  20. Korea Conorete Institute, Concrete Design Code, Kimoondang Publishing Company, Seoul, Korea, 2012, 342 pp.
  21. Murugesh, G. and Cormier, K., When Lighter is Better, ASPIRE, 2007, pp. 20-28.