Reinforcement of flexion in concrete beams with carbon fiber cloak: anchorage mechanism

Abstract

Detachment of FRP (fiber reinforced plastic) laminates from the bottom face of the beams is an undesirable and complex problem. A sudden failure occurs, before the expected capacity of the strengthened beam is reached and without making use of the high tensile strength of the strengthening material. The aim of this study is to investigate the flexural behavior of reinforced concrete beams strengthened by FRP laminates, made of carbon fiber mats embedded in an epoxy matrix and bonded to the bottom face of the beam. Emphasis is given to the use of anchorage systems which are fixed at the beam ends in order to avoid premature detachment of the laminate and consequently to increase the flexural capacity of the beam. Nine beams were divided into five groups according to the anchorage system utilized. One of anchorage system has proved to be very efficient, increasing the flexural capacity of the beams to about 20%, as compared to the beams without any anchorage and to 95% as compared to the beam without strengthening.