Comparative Nonlinear Behavior of Corroded Circular and Square RC Columns

This paper discusses performance of the reinforced concrete structures deteriorated by corrosion on basis of numerical simulation analysis. The purpose is to preliminarily investigate the idea of performance comparison of circular and square reinforced concrete columns under corroded conditions. Previous research carried out by the authors shows that equivalent area reinforced concrete (RC) columns exhibit similar load-displacement behavior under flexural and shear controlled conditions. The two types of columns deviate from this similarity after the corrosion of steel reinforcement present in the concrete. The change in the load-displacement behavior is highly dependent upon factors including the corrosion ratio, axial load, presence of web reinforcement etc., The experimentally verified 3D finite element modelling (FEM) program (COM3D) was used to investigate the seismic performance of the circular shaped and its equivalent area square shaped RC columns. The results show that the effect of mild corrosion (around 2% corrosion) on the load-displacement behavior of square RC columns is more significant as compared to circular RC columns at without axial load and at lesser main reinforcement ratio while a similar behavior or reverse trend is observed at higher main reinforcement ratios and for cases with 10% axial load. The effect of corrosion on the web reinforcement present in square columns is more pronounced as compared to circular columns at low main reinforcement ratios.