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Title |
Evaluation of Side-face Blowout Strength of SD700 Hooked Bars in Exterior Beam-Column Joint
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Authors |
심혜정(Hye-Jung Sim) ; 천성철(Sung-Chul Chun) ; 김문길(Mun-Gil Kim) |
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DOI |
https://doi.org/10.4334/JKCI.2018.30.6.591 |
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Keywords |
외부 보-기둥 접합부 ; 갈고리철근 ; 정착강도 ; 정착길이 exterior beam-column joint ; hooked bar ; anchorage strength ; development length |
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Abstract |
Due to the increase of high-rise buildings and mega structures, high-strength reinforcing bars are required to ensure economic efficiency and durability. In KCI(2012), however, the upper limit of design yield strength of hooked bars is specified as 600MPa. In this study, exterior beam-column joint tests using SD700 hooked bars were conducted to provide basic data to extend the limitation of yield strength. Test results show that side-face blowout failure occurred in all specimens except the specimens for which tests were stopped, for safety, after the load reached actual yield strength of the hooked bars. A comparison of the measured bar stresses with the predictions of the current design code shows that it is safe to use the current design provisions to 700MPa hooked bars. In addition, a total of 108 test results were evaluated using the equation of side-face blowout strength of Chun et al.’s model (2017), which takes account of the effects of side cover and transverse reinforcement and the average and coefficient of variation of the test-to-prediction ratios are 1.02 and 12%. It is possible to accurately and safely design the development length of SD700 hooked bars using Chun et al.’s model, irrespective of bar diameter and bar strength.
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