Structural Behavior of Slender High-Strength RC Columns Strengthened by Steel Angles

Abstract

This article presents an experimental and analytical study related to the structural behavior of slender RC columns with normal-strength concrete (NSC) and high-strength concrete (HSC) strengthened by steel angles and battens. Twelve specimens of slender RC columns were tested, which differed in terms of the compressive strength of the concrete, reinforcement ratio, and spacing between battens. Furthermore, the axial load was applied in the experimental test with three different eccentricities (, 2, and 4 mm). The structural behavior of the columns, such as the deflection, ultimate load, and mode of failure, was found to be significantly influenced by the strengthening. The ultimate load was increased by 5.43, 79.49, and 86.32% for the spacing between battens of 432, 288, and 192 mm, respectively, when compared with the unstrengthened column, which had 2-mm eccentricity. The ultimate load was increased by 42.86% for 192 mm, compared with the unstrengthened column, which had zero eccentricity. New analytical formulas were derived based on equilibrium equations and strain compatibility to estimate the ultimate load of slender columns with or without strengthening. The difference range in the ultimate load between the proposed formulas and experimental results of the current work and many previous researchers was .3–24.9%, and the average was 7.5%.