Capacity assessment of existing rc columns

Existing reinforced concrete (RC) members, designed in accordance with obsolete codes, are often characterized by high stirrup spacing. The collapse mechanisms generated by high stirrup spacing are typically related to the buckling of longitudinal reinforcement and can be accentuated when corrosion takes place. In this paper, new refined material constitutive laws for steel, including inelastic buckling and corrosion of reinforcement, are implemented in a fixed crack model suitable for RC elements subjected to cyclic loadings called the PARC_CL 2.1 crack model. The effectiveness of the proposed model is validated through comparison with available experimental data and analytical predictions. Finally, the proposed model is used to calibrate correction coefficients to be applied to current codes formulation for the ultimate rotational capacity prediction of non-conforming elements subjected to buckling phenomena and characterized by corrosion of reinforcing bars.