Retrofit of Reinforced Concrete Columns Using Partially Stiffened Steel Jackets

Abstract

This paper introduces an improved steel jacketing method to retrofit reinforced concrete columns with a square or rectangular section for enhanced strength and improved ductility. To retrofit an existing column, relatively thin steel plates were welded to form a rectilinear jacket for shear strength enhancement, and then additional confinement elements (stiffeners) with various types of desired configurations were welded to the potential plastic hinge regions to ensure a ductile behavior. A rational retrofit design procedure was suggested and evaluated through an experimental program. Five 1/3 scale model columns were tested under constant axial load of