50 GPa의 탄성계수를 가지는 GFRP 보강근 콘크리트 보의 처짐 실험에 의한 설계식 분석

초록

Corrosion in reinforced concrete has driven the adoption of noncorrosive alternatives, and GFRP rebars have emerged as one of the most widely used options owing to their economic viability and balanced performance. However, their elastic modulus is lower than that of steel, which limits full substitution in structural applications. In recent years, the modulus of GFRP has increased from 30–40 to ~60 GPa internationally and 50 GPa in domestic production; however, most existing design equations were calibrated for earlier generations of low-modulus GFRP. This study investigates the flexural behavior of two concrete beams reinforced with high-modulus GFRP rebars. Experimental load–displacement responses are compared with predictions from the Adam model, ACI 440.1R-06, CSA S806-12, and the latest ACI 440.11-22 provisions. All models accurately capture the initial slope in the uncracked region; however, they generally underestimate the actual stiffness and overpredict deflections because they are calibrated for low-modulus GFRP. These deviations increase after cracking, with the Adam equation exhibiting the largest discrepancy. This indeed reflects the limitations of existing models and shows that their usage should be approached with caution in applications where displacement control is critical.

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