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Title |
Evaluation on the Effectiveness of Supplementary V-ties on Flexural Ductility of Reinforced Concrete Columns
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Authors |
이혜진(Hye-Jin Lee) ; 양근혁(Keun-Hyeok Yang) ; 곽민경(Min-Kyoung Kwak) |
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DOI |
https://doi.org/10.4334/JKCI.2017.29.4.345 |
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Keywords |
columns ; supplementary crossties ; V-ties ; axial load level ; flexural ductility |
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Abstract |
This study evaluated the effectiveness of V-shaped ties as an alternative to the supplementary crossties specified in ACI 318-14 on the flexural ductility of reinforced concrete columns. From column specimens tested under constant axial loads and reversed cyclic lateral loads, the mode of failure and lateral load-lateral displacement relationship were measured according to the variation of the applied axial load levels. After the columns reached the peak lateral load capacity, the 90° hooks of the crossties gradually opened, which eventually caused premature buckling of the longitudinal reinforcement and severe crushing of the core concrete, whereas no V-ties were extracted from the core concrete until the column failure. As a result, the cumulative work damage indicators up to 80% of the peak lateral load for V-tie columns under the axial load level of 0.2, 0.4, and 0.55 was as much as 2.4, 2.3, and 5.2 times higher, respectively, than those of the companion crosstie columns. The superiority of the V-ties to the conventional crossties in enhancing the flexural ductility of columns became more prominent as the axial load level increases.
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