압축보강근이 없는 고탄성 GFRP 보강근 콘크리트 보의 장기처짐 분석

초록

This study experimentally investigates the long-term behavior of concrete beams reinforced with glass-fiber-reinforced polymer (GFRP) bars having an elastic modulus exceeding 50 GPa. Current design provisions, such as ACI 440.11-22 and CSA S806-12, calculate long-term deflection using empirical factors similar to those for steel reinforcement. However, because these factors are derived from low-modulus GFRP data, their application to modern high-modulus GFRP may be inappropriate. To address this issue, long-term loading tests were conducted using load levels, reinforcement ratios, and bar diameters as variables to quantify changes in creep and flexural stiffness. The results were used to evaluate existing codes and analyze the effects of reinforcement stiffness. The findings indicate that current factors inaccurately predict the time-dependent deflections of high-modulus GFRP-reinforced beams at high load levels. Thus, this study justifies the need for a new long-term deflection model tailored to high-modulus GFRP-reinforced members.

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