Analytical modeling of corroded RC columns considering flexure-shear interaction for seismic performance assessment

Abstract

Corrosion of transverse reinforcement can lead to significant shear capacity deterioration resulting in a ductile-designed reinforced concrete (RC) column to potentially fail in a shear manner. Increased risk of shear failure can be more significant for short shear-critical columns when corrosion occurs. Therefore, shear response can be a particularly important issue in seismic performance assessment of corroded RC columns. An efficient analytical model which can capture the shear capacity deterioration due to corrosion and the flexure-shear interaction behaviors of corroded columns is developed in this work. Corrosion effect on flexural behavior is accounted for through the appropriate modification of steel reinforcement, concrete and bond properties. Shear response is simulated by a new macro zero-length shear spring element, and its shear force-shear deformation relationship is modelled with the Ibarra-Medina-Krawinkler deterioration model that can capture strength and stiffness deterioration as well as pinching behavior. A calibration study is carried out based on a collection of experiments of corroded columns failed in shear. Subsequently empirical formulae for the determination of the modeling parameters of the shear spring are proposed. The proposed model is validated by simulating several corroded columns and compering the predictions obtained with the relevant test data. Results show that the proposed model is able to predict reasonably the overall hysteretic behavior. Corrosion effects on the seismic performance of RC columns are investigated with the proposed model. Results demonstrate that the flexure-shear interaction behaviors should be considered for seismic performance assessment of corroded columns.