Strain-based analytical model for predicting one-way shear strength of slender FRP-reinforced concrete beams with and without transverse reinforcement

초록

This study proposes a strain-based analytical approach for predicting the shear strength of slender concrete beams reinforced with fiber-reinforced polymer (FRP) longitudinal bars, with and without transverse reinforcement. The proposed model evaluates shear strength based on the interaction between the shear demand and shear capacity curves at potential critical cross-sections. For each potential critical cross-section, the shear demand curve is obtained through nonlinear moment-curvature analysis and the shear capacity curve is constructed accounting for the contributions of the compression zone, cracked tension zone, and FRP stirrups. The model considered the distinct material properties of FRP bars and bond characteristics at the FRP reinforcement-concrete interface. The model reliability was validated through case studies and a database of 411 FRP-RC beam specimens. Comparative analysis with state-of-the-art design codes and existing theoretical models demonstrated that the proposed model provides improved accuracy, achieving mean shear strength ratios of 1.04 and 1.09 for beam databases with and without stirrups, respectively, with the lowest dispersion (COV = 16.9% and 16.6%) and the smallest average absolute error. Furthermore, parametric analyses indicated that the strainbased analytical approach using the principles of structural mechanics can effectively explain the mechanisms governing one-way shear strength through the interaction between shear demand and shear capacity curves of the critical section. Therefore, the model is expected to be useful for design and assessment applications for concrete members with FRP rebars.

키워드