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Evaluation of Axial Behavior of Strengthened Columns according to Different Peripheral Closed Hoops in Jacket Section

확대단면에서 폐쇄형 외부 띠철근 배근 방법에 따른 보강기둥의 중심축하중 거동 평가

  • Received : 2018.12.28
  • Accepted : 2019.06.24
  • Published : 2019.07.30

Abstract

This study examined the effect of various arrangement methods for forming peripheral closed hoops in the jacket section on the axial behavior of section enlargement strengthening columns. Four types of peripheral closed hoops arranged in the jacket section were prepared as follows: 1) Closed connection of prefabricated bar units (column P); 2) V-clip installation across the overlapped legs of channel-type bars (column V); 3) Use of glass fiber mesh for an alternative of steel bars (column F); and 4) combination of prefabricated bar units and glass fiber mesh (column PF). The V-clip is designed to form the closed hoops in the jacket section using the overlapped channel-type bars, preventing the opening of the channel bar legs. The glass fiber mesh is to examine the feasibility to apply for closed hoops in the jacket section as an alternative for steel bars, considering the easy construction. In the jacket section of all the strengthened columns, V-ties were arranged for supplementary ties, avoiding the interruption of the existing column. The axial stiffness and strength of the strengthened columns were insignificantly affected by the arrangement methods of closed hoops in the jacket section. The axial ductility ratio of the strengthened columns P, V, and PF was enhanced more than twice of that measured in the non-seismic existing column. However, the column F exhibited a lower ductility than the other strengthened columns because of the fracture of the mesh at the ultimate strength of the column. The V-clip approach was favorable to enhance the ductility of the strengthened column, preventing the opening of the legs of channel-type bars.

Keywords

Acknowledgement

Supported by : 국토교통과학기술진흥원

References

  1. ACI Committee 318 (2014). Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary, American Concrete Institute, Farmington Hills, Michigan, USA.
  2. Hwang, Y. H., Yang, K. H., Sim, J. I., & Choi, Y. S. (2018a). Evaluation of Axial Behavior of Columns Strengthened with Different Transverse Reinforcements in Jacket Section, Journal of the Korea Institute for Structural Maintenance and Inspection, 22(6), 81-88. https://doi.org/10.11112/JKSMI.2018.22.6.081
  3. Hwang, Y. H., Yang, K. H., Sim, J. I., & Choi, Y. S. (2018b). Evaluation fo Axial Compressive Performance of Section Enlargement Strengthening Columns with Prefabricated Reinforcement Units in the Jacket Section, Journal of the Korea Concrete Institute, 30(6), 609-616. https://doi.org/10.4334/JKCI.2018.30.6.609
  4. Hwang, Y. H., Yang, K. H., Sim, J. I., & Choi, Y. S. (2018c). Evaluation of Axial Compressive Performance of Section Enlargement Strengthening Columns with Supplementary V-Ties and V-Clips in the Jacket Section, Journal of the Korea Concrete Institute, 31(5), publication in Oct.
  5. Kwon, H. J., Yang, K. H., & Sim, J. I. (2018). Proposals of Reliable Shapes of Supplementary V-ties for Section Jacketing Method of Columns, Journal of the Korea Institute of Building Construction, 18(2), 99-107. https://doi.org/10.5345/JKIBC.2018.18.2.099
  6. Lee, K. I., Yoon, H. S., & Yang, K. H. (2018). Compressive and Adhesive Strengths of Mortars using Polymer and Ultra-Rapid-Hardening Cement, Journal of the Korea Institute of Building Construction, 18(4), 329-335. https://doi.org/10.5345/JKIBC.2018.18.4.329
  7. Jin, L., Du, M., Li, D., Du, X., & Xu, H. (2017). Effects of Cross Section Size and Lateral Rebar on the Behavior of Short Squared RC Columns under Axial Compression, Engineering Structures, 142, 223-239. https://doi.org/10.1016/j.engstruct.2017.04.002
  8. Ozcebe, G., & Saatcioglu, M. (1987). Confinement of Concrete Columns for Seismic Loading, ACI Structural Journal, 84(4), 308-315.
  9. Penelis, G. G., & Kappos, A. J. (1997). Earthquake resistant concrete structures, CRC Press, Florida, USA.
  10. Saatcioglu, M., & Razvi, S. R. (1992). Strength and Ductility of Confined Concrete, Structural Engineering, ASCE, 118(6), 1590-1607. https://doi.org/10.1061/(ASCE)0733-9445(1992)118:6(1590)
  11. Troung, G. T., Kim, J. C., & Choi, K. K. (2017). Seismic Performance of Reinforced Concrete Columns Retrofitted by Various Methods, Engineering Structures, 134, 217-235. https://doi.org/10.1016/j.engstruct.2016.12.046
  12. Yang, K. H., & Kim, W. W. (2016). Axial Compression Performance of Reinforced Concrete Short Columns with Supplementary V-Shaped Ties, ACI Structural Journal, 113(6), 1347-1356. https://doi.org/10.14359/51689159