Shape memory alloy (SMA) rebars have been investigated as a seismic retrofit for reinforced concrete (RC) columns because of their superelastic behavior and self-centering capability. Since SMA rebars are more expensive than conventional steel rebars, they should be selectively used in the plastic hinge region, where seismic damage concentrates, which requires a reliable estimate of the plastic hinge length. In this study, a model for predicting the plastic hinge length of circular SMA-RC columns was developed using extreme gradient boosting. A numerical database of 52,200 cases was constructed by combining column and section dimensions from circular RC column databases with probabilistically sampled material properties, of which 37,235 valid cases were used for model development. Moment-curvature analysis of sampled column sections was then performed to calculate the plastic hinge length from the maximum section moment and the moment at the forward transformation start strain of the compression-side SMA rebar. The proposed model achieved a coefficient of determination (R2) of 0.998 and a root mean square error (RMSE) of 0.010, whereas the existing equations for SMA-RC columns yielded negative R2 values. Shapley additive explanations analysis was then conducted to interpret the model, showing that the aspect ratio, transverse reinforcement ratio, and SMA transformation characteristics had the strongest influence on the predicted plastic hinge length. By combining predictive accuracy with interpretability, the proposed model can serve as an effective data-driven tool for estimating the plastic hinge length of SMA-RC columns.

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1. 서 론
2. 데이터셋 구축
    2.1 기둥 단면 데이터베이스
    2.2 재료 물성치의 확률론적 분포 및 데이터 샘플링
3. SMA-RC 기둥의 소성힌지 길이 예측모델 개발
    3.1 SMA-RC 단면 모델링
    3.2 SuperelasticSMA 재료 모델 검증
    3.3 소성힌지 길이 판정 방법
    3.4 XGBoost 기반 소성힌지 길이 예측 모델과 하이퍼파라미터최적화
    3.5 예측 결과 및 기존 예측식과의 비교
4. 예측 모델의 SHAP 분석 결과
    4.1 SHAP 분석 결과
    4.2 변수의 경향성
5. 결 론
/ 감사의 글 /
/ REFERENCES /

• 김영우(한양대학교 건설환경공학과 석사과정) | Kim Youngwoo (M.S. Student, Department of Civil and Environmental Engineering, Hanyang University)
• 이건찬(한양대학교 건설환경공학과 박사수료) | Lee Gun Chan (Ph.D. Candidate, Department of Civil and Environmental Engineering, Hanyang University)
• 이창석(국립금오공과대학교 건축학부 조교수) | Lee Chang Seok (Assistant Professor, School of Architecture, Kumoh National Institute of Technology)
• 전종수(한양대학교 건설환경공학과 교수) | Jeon Jong-Su (Professor, Department of Civil and Environmental Engineering, Hanyang University) Corresponding author