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Lateral Confinement Effectiveness of V-Shaped Supplementary Ties in RC Columns subjected to Axial Compressive Loads

중심 압축하중을 받는 RC 기둥에서 V형 보조띠철근의 횡구속 효과

  • Yang, Keun-Hyeok (Department of Plant.Architectural Engineering, Kyonggi University)
  • Received : 2015.12.16
  • Accepted : 2016.03.11
  • Published : 2016.03.30

Abstract

This study proposed a simplified supplementary tie arrangement method in reinforced concrete columns using V-shaped bars as an alternative to the crossties specified in ACI 318-11 provision. Eight RC column specimens were prepared to examine the effectiveness of the V-ties on the compressive performance of columns and concrete confinement. The test parameters investigated were the type of supplementary ties, the amount of transverse reinforcement, and concrete compressive strength. Test results showed that the axial capacity of V-tie columns can be conservatively estimated using ACI 318-11 equations. With the spalling of the concrete cover, 90-degree hooks of crossties were gradually opened, whereas no V-ties were extracted from core concrete. As a result, higher axial ductility ratios were obtained for V-tie columns than for the companion crosstie columns. This trend was more notable as the amount of transverse reinforcement decreases and concrete compressive strength increases. Ultimately, a greater effective confinement pressure is obtained in V-tie arrangement than the conventional crosstie arrangement.

Keywords

Acknowledgement

Supported by : Kyonggi University

References

  1. ACI 318-11 (2011). Building Code Requirements for Structural Concrete and Commentary, American Concrete Institute, Farmington Hills, USA.
  2. Azizinamini, A., Kuska, S. S. B., Brungardt, P., & Hatfield, E. (1994). Seismic behavior of square high-strength concrete columns, ACI Structural Journal, 91(3), 336-345.
  3. Bae, S. (2005). Seismic performance of full-scale reinforced concrete columns, Ph.D. Dissertation, The University of Texas at Austin, USA.
  4. CEB-FIP (1999). Structural Concrete: textbook on behaviour, design and performance, International Federation for Structural Concrete, Switzerland.
  5. Chung, H. S., Yang, K. H., Lee, Y. H., & Eun, H. C. (2002). Strength and ductility of laterally confined concrete columns. Canadian Structural Journal, 29(6), 820-830.
  6. Fafitis, A., & Shah, S. P., (1985). Predictions of ultimate behavior of confined columns subjected to large deformations, ACI Structural Journal, 82(4), 423-433.
  7. Kim, W. W., Mun, J. H., & Yang, K. H. (2015). Simplified model for the stress-strain relationship of confined concrete, Journal of the Architectural Institute of Korea: Structure & Construction, 31(4),79-86.
  8. Kim, W. W., & Yang, K. H. (2015). Effect of bending angle and embedment length on the bond characteristics of V-shaped tie reinforcement, Journal of the Korea Institute of Building Construction, 15(5), 465-471. https://doi.org/10.5345/JKIBC.2015.15.5.465
  9. Lukkunaprasit, P., & Sittipunt, C. (2003). Ductility enhancement of moderately confined concrete tied columns with hook-clips, ACI Structural Journal, 100(4), 422-429.
  10. Mander, J. B., Priestley, M. J. N., & Park, R. (1988). Observed stress-strain behavior of confined concrete, Journal of Structural Engineering ASCE, 114(8), 1827-1849. https://doi.org/10.1061/(ASCE)0733-9445(1988)114:8(1827)
  11. Ozcebe, G. & Saatcioglu, M. (1987). Confinement of concrete columns for seismic loading, ACI Structural Journal, 84(4), 308-315.
  12. Razvi, S. R., & Saatcioglu, M. (1999). Confinement model for high strength concrete, Journal of Structural Engineering ASCE, 125(3), 281-289. https://doi.org/10.1061/(ASCE)0733-9445(1999)125:3(281)
  13. Saatcioglu, M., & Razvi, S. R. (1992). Strength and ductility of confined concrete, Journal of Structural Engineering ASCE, 118(6), 1590-1607. https://doi.org/10.1061/(ASCE)0733-9445(1992)118:6(1590)
  14. Sheikh, S. A., & Khoury, S. S. (1993). Confined columns with stubs, ACI Structural Journal, 90(4), 414-431.
  15. Sheikh, S. A., & Uzumeri, S. M. (1982). Analytical model for concrete confinement in tied columns, Journal of Structural Engineering ASCE, 108(ST12), 2703-2722.
  16. Yang, K. H. (2015). Development of a simplified V-shared ties for seismic design of reinforced concrete columns. Technical Report, Kyonggi University.
  17. Yang, K. H., Mun, J. H., Cho, M. S., & Kang, T. H. K. (2014). Stress-strain model for various unconfined concretes in compression, ACI Structural Journal, 111(4), 819-826.