Capacity assessment of existing RC columns taking into account bi-axial shear failure

Several scenarios can trigger bi-axial shear in reinforced concrete (RC) vertical members such as wind actions, earthquake, fire, and explosions. In this paper, bi-axial shear scenarios are analysed and the capacity of corroded RC members such as columns or bridge piers is evaluated. Firstly, the interaction between bending moment and shear force, combined with cyclic degradation is analytically evaluated. To this aim, the recent formulation proposed by Biskinis and Fardis for the assessment of the uni-axial shear resistance is extended to plot the bi-axial failure criterion, while the ductility is evaluated by considering the effect of the bi-axial bending moments and the applied axial force. Finally, design provisions are given in order to propose adjustments to the formulations provided by standard Codes and Guidelines that allow to take into account the effect of corrosion in the assessment of the bia-axial shear resistance of RC members.