Biaxial Bending of Reinforced Concrete Columns Strengthened with Externally Applied Reinforcement in Combination with Confinement

This paper presents an analytical model for the analysis of reinforced concrete (RC) members with rectangular cross sections, strengthened in flexure with various types of externally applied reinforcement (near-surface-mounted [NSM] or externally bonded [EBR]), in combination with composite material confining jackets. The model takes into account simple but realistic constitutive laws for the constituent materials and yields, through a simplified procedure, the resistance of cross sections subjected to biaxial bending combined with axial loading. Verification of the analytical approach is provided by comparing the model predictions with existing test results published in the literature. The analytical formulation is then implemented in a user-friendly computer program, which is used to perform a number of parametric studies on the role of various factors (for example, reinforcing ratios, level of axial force, level of confinement, type of external reinforcement, and confining materials) in section resistance.