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Title |
Structural Behavior and Design of Anchor Reinforcement in Anchoring to Concrete
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Authors |
천성철(Sung-Chul Chun) ; 안성문(Seong-Moon Ahn) |
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DOI |
https://doi.org/10.4334/JKCI.2025.37.3.277 |
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Keywords |
앵커철근; 설계기준; 스트럿-타이 모델; 콘크리트 브레이아웃 anchor reinforcement; design code; strut-and-tie model; concrete breakout |
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Abstract |
According to KCI 2021 and ACI 318, the strength by anchor reinforcement can replace concrete breakout strength, provided that the development requirements for the reinforcement are met in both directions of the anticipated breakout failure surface. However, due to the limited research on anchor reinforcement, the design codes do not specify upper limits for the diameter, yield strength, or design strength of anchor reinforcement. Previous studies on anchor reinforcement were re-analyzed, and anchor reinforcement design was performed using a Strut-and-tie model. The re-analysis showed that when the development length and placement of anchor reinforcement complied with code provisions, the strengths averaged twice the expected values. Even when cracks formed along the anticipated failure surface, the anchor reinforcement limited crack widening, thus allowing partial preservation of the concrete breakout strength. Furthermore, reinforcement placed outside the effective width defined by the code provisions also contributed to the anchor reinforcement capacity. From the Strut-and-tie model analysis of anchors in tension with anchor reinforcement, it was found that proper placement of anchor reinforcement according to code requirements could achieve more than three times the concrete breakout strength. In addition, the presence of edge reinforcement further enhanced this strength. Because the anchorage conditions for anchor reinforcement are more favorable than those of standard straight or hooked bars specified in design codes, it is anticipated that the strength of anchor reinforcement can be fully realized regardless of its diameter. However, future experimental studies are needed to validate the performance of large-diameter, high-strength anchor reinforcement.
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