Shear behavior analysis of <scp>ETS</scp> ‐ <scp>FRP</scp> retrofitted beams based on the softened membrane model

Abstract Comprehensive analytical modeling of the shear behavior of reinforced concrete (RC) beams strengthened with fiber‐reinforced polymer (FRP) composites is increasingly important, especially when implemented using cost‐effective tools. This study enhances the softened membrane model (SMM), commonly used for membrane RC elements subjected to shear action, to simulate the shear performance of RC beams retrofitted with FRP bars using embedded through‐section (ETS) technique. Various combinations of concrete and steel constitutive laws, along with softening factor formulations, are evaluated to determine the most effective SMM configuration. As an additional advancement, the ETS‐FRP shear contribution is analyzed using a bonding‐based approach and integrated into the most effective SMM. Validation against experimental data shows high accuracy in predicting the beam shear capacity, with a mean computed‐to‐tested shear strength ratio of 0.96 and a coefficient of variation of 0.13. The developed SMM also captures the full load–deflection response of the beams. The computation with the bonding‐based ETS‐FRP model yields conservative predictions. Analyses of various softening and shear aggregate interlocking models confirm that the enhanced SMM is computationally feasible.