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Title |
Lap Splice Length Influence in Slabs with 180-Degree Standard Hooked Bars at Separately Cast Joints
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Authors |
정유진(Yu-Jin Jung) ; 이문석(Moon-Seok Lee) ; 손동희(Dong-Hee Son) ; 배백일(Beak-Il Bae) ; 최창식(Chang-Sik Choi) |
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DOI |
https://doi.org/10.4334/JKCI.2025.37.6.747 |
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Keywords |
180도 표준갈고리 철근; 이음; 정착길이; 부착강도 180-degree standard hooked bar; lap splice; development length; bond strength |
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Abstract |
This study analyzed the behavior and influence of lap splice length in precast concrete slabs incorporating 180-degree standard hooked bars. Complex failure patterns involving splitting failure, side cover spalling, and prying action were simultaneously observed. As the splice length increased, the stress level along the entire bar length generally increased, and, as with hooked bar development, stress transfer was predominantly governed by the straight and bent portions of the hooked bars. In addition, bar stress was transferred primarily through bond forces, while the contribution of bearing forces was relatively minor. When the KDS development length provisions were applied to lap splices using standard hooked bars without applying the modification factor, an equivalent or higher level of performance was achieved. However, when the modification factor was applied, the KDS development equations were found to overestimate the lap splice strength. Therefore, it is necessary to revise the current design provisions to ensure the required safety margin for development length when using hooked bars for lap splicing.
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