Modeling of Corroded FRP-Wrapped Reinforced Concrete Columns in Axial Compression

Abstract

This paper discusses the mechanical behavior of reinforced concrete columns wrapped with fiber-reinforced polymer (FRP) sheets. A numerical routine was developed to predict the behavior of the columns using a step-by-step technique. The routine is based on an existing model and was modified to account for confinement provided by the traditional steel as well as the external FRP wraps. Several empirical equations for the confined concrete were calibrated with results from experimental tests from different published papers. The most accurate equation was incorporated into the routine to predict the stress-strain relation of the column up to failure. A different confinement to the outer concrete cover and the inner core was used to account for the FRP wraps and the transverse steel. The model was calibrated with experimental results from different experiments on FRP-wrapped reinforced concrete columns.The model was taken one step further by using it to predict the behavior of reinforced concrete columns, with a combination of steel corrosion and CFRP wraps. The columns modeled were subjected to harsh corrosive environment over 44 months. The model successfully predicted the load deformation in both axial and circumferential directions in corroded and intact columns, both wrapped and unwrapped, with good accuracy. The analysis forms a solid foundation for accurate evaluation of the effect of corrosion and wrapping on reinforced concrete columns.