GFRP 보강근 굽힘부의 등가 환산 단면법을 이용한 유한요소해석 모델링 기법

초록

Glass fiber–reinforced polymer (GFRP) bars exhibit critical strength degradation at bent portions owing to crinkling, resulting in a physical reduction of the effective cross-section. Current FE modeling practice typically reduces only material strength without accounting for the accompanying loss of stiffness. This study proposes an equivalent cross-section method that directly accounts for physical cross-sectional loss and compares it with the conventional strength-reduction method using ABAQUS. A two-dimensional beam analysis of bent GFRP bars with three diameters (13, 16, and 19 mm) showed that normalized bend strength depends solely on the diameter ratio, forming a single quadratic curve. The equivalent diameter reduced axial stiffness to 68%–76% and flexural stiffness to 47%–58%. A three-dimensional nonlinear analysis of a concrete sound barrier foundation revealed that the strength-reduction method underestimated the ultimate load capacity by approximately 11% owing to premature GFRP rupture at the artificially reduced threshold. Therefore, the equivalent cross-section method provides a more physically consistent FE modeling approach for bent GFRP bars.

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