Thin fibre-reinforced concrete jackets for improving the seismic response of reinforced concrete members : experimental and numerical results

Abstract

The paper presents a comprehensive study of the behavior of reinforced concrete beams strengthened by thin fibre reinforced concrete (FRC) jackets. The FRC jackets were made of high strength concrete with the addition of hooked steel fibers. The reinforced concrete beams that were strengthened with the jacket were made of conventional C20/25 concrete. Two cases were considered: a) beams with longitudinal reinforcement and closely spaced stirrups, and b) beams with longitudinal reinforcement and no transverse reinforcement. For the strengthening method, two cases were considered: a) thin FRC jackets with longitudinal and transverse reinforcement, and b) thin FRC jackets reinforced with a light structural steel mesh. The thickness of the FRC jacket was 3 cm. Combining the above cases, four (4) types of beams were produced, which were tested under cyclic 4-point bending. The tested beams were simulated numerically. The modelling procedure effectively took into account the various nonlinearities present in the physical model. The significant contribution of the FRC jackets in strengthening and improving the overall behavior of the concrete beams is shown by the experimental results (Paratheoharis, 2007) and the predictions of the numerical simulation.