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초록

Bond stress, a key factor governing load transfer between concrete and reinforcing bars, greatly influences the structural performance of reinforced concrete (RC) structures and requires careful consideration during design. This study proposes a design equation for bond strength that reflects the bond characteristics between beam longitudinal reinforcement and concrete penetrating interior beam-column joints in RC moment-resisting frames under cyclic loading. Bond tests were conducted on 33 specimens that directly simulated the stress state of interior joints to evaluate the effects of concrete compressive strength and column axial load ratio on bond performance. The proposed bond strength equation was developed by incorporating these influencing factors and the contribution of transverse reinforcement within the joint. The model exhibited a coefficient of variation of 20.6 % and a coefficient of determination (R2) of 0.817, indicating higher predictive accuracy than existing design criteria. Furthermore, the required column depth was derived from the bond length calculation using the proposed equation, and the predicted failure modes showed good agreement with experimental observations.

키워드