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Title |
Anchorage Behavior and Strengths of D22 SD600 Reinforcing Bars in Compression Terminated in Exterior Beam-Column Joint
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Authors |
성민규(Min-Kyu Seong) ; 천성철(Sung-Chul Chun) |
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DOI |
https://doi.org/10.4334/JKCI.2018.30.5.505 |
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Keywords |
외부 보-기둥 접합부 ; 정착강도 ; 측면파열파괴 ; 부착 ; 지압 beam-column joint ; anchorage strength ; side-face blowout failure ; bond ; bearing |
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Abstract |
Due to the favorable effects of end bearing of reinforcing bars, reinforcing bars in compression are more advantageous for anchorage strength than are reinforcing bars in tension. In current design codes, however, the standard development length of deformed bars in compression is longer than the standard development length of hooked bars in tension. If modification factors of cover and confining reinforcement are included, the difference between the development lengths of bars in compression and hooked bars in tension becomes greater. This phenomenon is caused by a lack of studies on anchorage of reinforcing bars in compression. In this study, to evaluate the behavior of anchorages in compression, anchorage tests of straight and hooked bars terminated within exterior beam-column joints were performed. The experimental variables include embedded length, side-cover and transverse reinforcement for two types of anchorage; straight and hooked bars. Test results show that the main failure mode is splitting by bond mixed with concrete breakout of back-cover by end-bearing reinforcing bars. As the embedded length increases, the strength developed by the bond increases, but the strength developed by the bearing does not improve. The strengths developed by bond and bearing increase in proportion to the side-cover thickness. No effects of transverse reinforcement on bar stress is observed in the straight bars, but the bearing strength increases in the hooked bars. Because previous models do not consider overlap of failure modes of splitting by bond and concrete breakout by end bearing, the previous models cannot properly predict the experimental values.
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