Numerical simulation and experimental analysis of plastic hinge length of reinforced concrete columns under monotonic flexure and constant axial load

This article investigated test results of 81 reinforced concrete columns under monotonic flexure load via numerical simulation and experimental studies from the literature to comprehensively discuss the parameters that influence plastic hinge length. Moreover, it proposed a simplified method, based on the compressive strain of longitudinal reinforcing bars, and a new expression to estimate plastic hinge length, based on axial load ratio, shear span-depth ratio, and longitudinal reinforcement ratio. In addition, it compares and discusses analytical expressions to estimate plastic hinge reported in previous research. The analysis shows that axial load ratio, shear span-depth ratio, and longitudinal reinforcement ratio strongly influence both lateral load-displacement responses and plastic hinge length. Furthermore, the proposed simplified method is adequate for estimating plastic hinge length. Finally, the results show that the equation proposed as a way of estimating the plastic hinge length provides satisfactory predictions for reinforced concrete columns under monotonic flexure.