BEHAVIOURS OF RC DEEP BEAMS STRENGTHENED IN SHEAR USING HEMP FIBER REINFORCED POLYMER COMPOSITES

Abstract

This paper presents an experimental study on externally bonded hemp fiber reinforced polymer composites reinforced concrete deep beams to investigate the efficiency of hemp fibers in shear strengthening. Reinforced Concrete (RC) deep beam is a beam with the depth comparable to the span length. There are several applications of RC deep beams, such as transfer girders in tall buildings, a wall of water tanks, and footings. Despite a number of research works on strengthening RC deep beams, a current literature review demonstrated no studies on the use Hemp fiber to increase the shear strength of RC deep beams. Hemp fibers are natural fibers which can be obtained from plants. Hemp fibers are externally applied to the beam’s surface using epoxy resin. A series of three-point loading tests were conducted on natural hemp fiber strengthened reinforced concrete deep beams. The research parameters included hemp fiber thickness and strengthening configuration, i.e. hemp fiber applied onto two or three sides (U shape). Test results indicated that hemp fiber reinforced polymer composite was capable of enhancing the ultimate load and deflection of RC deep beams. In general, the experimental results demonstrated a higher increase in the shear strength when the thickness of the hemp fiber was increased. Strengthening configuration also has a great impact on the strength and ductility. The U-shaped strengthening with hemp fiber applied onto the side and bottom faces of the beam was superior to strengthening on side faces only.