Experimental Investigation of Reinforced Concrete Beams Strengthened by Skeleton Steel and Ferrocement Cover

Abstract

The method of strengthening reinforced concrete beams using ferrocement and skeleton steel attached on the side faces of the beam is presented in this paper. The study is based on an experimental program carried out on five beams designed to fail in shear. One of the specimens is control specimen and the others are strengthened specimens with various skeleton web steel arrangements and ferrocement covers. The ferrocement is 20 mm thick, thus adding little extra dead weight to the beam. The difference among strengthened specimens is the shape of ferrocement cover (side cover or U-cover), spacing of additional external web reinforcements and surface roughness between original beam and ferrocement cover. Results from tests, such as ultimate strength, ductility and cracking pattern of strengthened specimens are compared with control specimen. Load-deflection responses are obtained up to the failure or the capacity limit of measuring devices. The performance of the various proposed methods are analyzed using conventional ACI procedures. The effect of various parameters, such as shapes of ferrocement cover (side or U), spacing and configuration of external web reinforcements and surface roughness are discussed. Results show that the proposed strengthening techniques improve ductility, ultimate strength and produce desirable flexural failure mode.