Anchoring influence in RC beams flexural strengthening using CFRP lamellas

Since there is a real bond issue between the support layer (concrete) and the epoxy resin used to bond the CFRP lamellas, in most situations the failure of the strengthened element occurs due to debonding mechanism, long before the capacity of the lamella is reached. This phenomenon usually arises because of the lack of attention paid to the preparation of the support layer by neglecting the concrete's quality, by poor knowledge of technological requirements or by poor qualification of the workers who apply this strengthening technique. In order to overcome this bond issue that could lead to important faults and reduced effect of strengthening intervention, a series of anchoring solutions (mechanisms) were proposed, two of these being already experimentally tested in the laboratory. The first proposal involves the anchoring of the lamella at both ends using steel plates connected to the concrete elements by bolts. The second solution suggests the anchoring of the lamella on its entire length using distributed steel bolts that are chemically anchored in the concrete element.