Effect of Chloride Corrosion on Eccentric-Compression Response of Concrete Columns Reinforced with Steel-FRP Composite Bars

Abstract

This paper presents test results of eccentrically loaded concrete columns reinforced with steel fiber–reinforced polymer (FRP) composite bars (SFCBs) subjected to chloride corrosion. The first stage of the experimental work explored the tensile and compressive tests of various reinforcements (SFCBs with different cross section, steel, and FRP bars) used in the large reinforced-concrete (RC) columns after chloride corrosion with or without sustained stresses. The results showed that the tensile and compressive stress–strain relationships of SFCBs are characterized by stable secondary (post-yield) stiffness. The second stage of the testing investigated the structural performance of RC columns with various amounts and types of reinforcements, slenderness ratio, applied load eccentricity, and chloride corrosion rate. The results showed that the effect of reinforcements on eccentric compression behavior is significant. The deformation and crack width of SFCB-RC columns, respectively, decreased by 12.2%–52.6% and 8.5%–71.0%, while the load capacity improved by 0.9%–18.8%, when compared with the corresponding FRP-RC columns having the same eccentricity and reinforcement ratio. The use of SFCBs as the reinforcement of RC columns, especially with high reinforcement ratio or SFCBs having high area ratio of inner steel to SFCB, is beneficial to reducing the deflection and crack width as well as improve the bearing capacity utilization coefficients under a serviceability limit state.