PERFORMANCE OF REINFORCED CONCRETE BEAMS STRENGTHENED BY HYBRID FRP LAMINATES Abdelhady Hosny 1 , Hamdy Shaheen 2 , Amr Abdelrahman 3 , Tamer Elafandy 4 1 Emeritus Prof., Structural Engineering Dept., Ain Shams University, Cairo, Egypt 2 Prof., RC Dept., Housing and Building Research Center, Giza, Egypt 3 Associate Prof., Structural Engineering Dept., Ain Shams University, Cairo, Egypt 4 Assistant Lecturer, RC Dept., Housing and Building Research Center, Giza, Egypt ABSTRACT In the last two decades, use of advanced composite materials such as Fiber Reinforced Polymers, (FRP), in strengthening reinforced concrete, (RC), structural elements have been increasing. Researches and design guidelines concluded that externally bonded FRP could increase the capacity of RC elements efficiently. However, the linear stress-strain characteristics of FRP up to failure and lack of yield plateau have a negative impact on the overall ductility of the strengthened RC elements. Use of hybrid FRP laminates, which consists of a combination of either carbon and glass fibers or glass and aramid fibers change the behavior of the material to a non-linear behavior. This paper aims to study the performance of reinforced concrete beams strengthened by hybrid FRP laminates. This paper presents an experimental program conducted to study the behaviour of RC beams strengthened with hybrid fiber reinforced polymer (HFRP) laminates. The program consists of a total of twelve T-beams with overall dimensions equal to 460 x 300 x 3250-mm. The beams were tested under cyclic loading up to failure to examine its flexural behaviour. Different reinforcement ratios, fiber directions, locations and combinations of carbon fiber reinforced polymer (CFRP) and glass fiber reinforced polymer (GFRP) laminates were attached to the beams to predict the best strengthening scheme. Different percentages of steel reinforcement as well as load level at the time of strengthening were also used. An analytical model based on the stress-strain characteristics of concrete, steel and FRP was adopted. Keywords: Ductility, Flexure, FRP, Repair, Hybrid, Rehabilitation and Strengthening. 1. INTRODUCTION In the last few decades, moderate and severe earthquakes stroke different places in the world causing severe damage to reinforced concrete, (RC), structures. This requires upgrading of RC structures to resist more loads. In addition to the several advantages of FRP in strengthening, such as no corrosion characteristic, lightweight and high strength, this technique does not result in an increase in the stiffness of the structure