프리캐스트 슬래브에서 180도 갈고리 철근 겹침이음의 거동에 대한 실험적 연구

초록

In precast concrete (PC) structures, hooked bars have attracted attention as an alternative to straight bars, as they can achieve sufficient anchorage performance with shorter lap lengths, thereby improving constructability and cost efficiency. When determining lap lengths between PC members, the development length equations for hooked bars specified in current design codes (ACI 318-25, KDS 14 20 52) are derived from beam-column joint tests, and thus their direct applicability to hooked bar lap splices is limited. This study experimentally investigates the performance of 180° hooked bar lap splices by testing 10 precast slab specimens under four-point bending. The key variables considered were splice length, bar diameter, concrete compressive strength, and yield strength of reinforcement, which were determined based on the ACI 318-25 hooked bar development length equation. Splice lengths were set to 0.3-1.0 times the code-based development length to examine the effective lap length of hooked bars required in practice. Test results indicated that the bar stresses measured in spliced specimens were 1.07-1.08 times greater than the stresses predicted by the KDS 14 20 52 equations, suggesting that the current provisions can be reasonably applied to estimate lap splice lengths of 180° hooked bars.

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