Effect of Corrosion Location and Transverse Reinforcement on Flexural-Ductile Response of Reinforced Concrete Beams

Abstract

Concern about premature ageing and deterioration of reinforced concrete (RC) structures primarily stems from reinforcement corrosion. The reinforcement corrosion not only reduces the effective cross-section of reinforcing bars but also causes a severe reduction in the structural performance and service life of RC structures. This study aims to analyze the effect of varying corrosion levels on the load-bearing ability of RC beams configured with varying amounts of transverse reinforcement. The idea pertinent to this study is to develop and validate a 3D finite element numerical model of RC beams and subsequently simulate the corrosion deterioration to assess the effect of corrosion deterioration on the flexural response of RC beams. The beam models have been analyzed with a four-point simply supported bending flexural test. For concrete-steel interaction simulation, the cohesive surface interaction method proved to be most suitable as the results aligned well with the analytical results. Loss of bond in concrete-rebar interface due to decrease in mechanical interlock is calculated. The concrete Damage Plasticity model is adopted for calculating concrete's confined and unconfined strength in tension and compression. A parametric study is also performed to investigate varying corrosion percentages on residual capacity, stiffness, energy dissipation and behaviour of corroded beams. Flexural strength response due to spacing of transverse reinforcements as per different Indian standard codes is analyzed. Spalling stress is calculated analytically and used in simulation data for more precise results. The results indicate a notable reduction in loaddeflection behaviour due to concrete spalling, deterioration of rebars ribs, loss in mechanical interlock mechanism and yield strength. The structure undergoes an absolute brittle failure at very high corrosion levels due to a complete steel-concrete bond loss. A good correlation between the developed FE model and experimental load-deflection curves was observed, with variability in ultimate load-bearing capacities of less than 5% for all the cases.