FRP composites are becoming a material of choice in an increasing number of rehabilitation and retrofitting projects around the world. Depending on the design objectives, these materials can be used to improve one or more of the structural member characteristics, such as the load capacity, ductility and even durability. Design of structural strengthening applications using externally bonded FRP composites is usually based on conventional design approaches with improvement to account for the presence and characteristics of the FRP material. Non-conventional design issues that are specific to the type of application require special considerations for their proper inclusion in the design process. One such design issue is the debonding problems in externally bonded FRP strengthening applications that have been a concern and a research challenge since the initial development stages of the strengthening method. End-peeling has governed a large interest and several debonding models have been presented. However, interfacial peeling at flexural cracks has not attained the same focus - even though this debonding failure is most likely more common. This paper presents laboratory tests of concrete beams strengthened in flexure with CFRP epoxy bonded plates. Wrapping with CFRP sheets was applied in order to try to localize the failure initiation. Concrete cracking as well as debonding initiation and propagation was possible to observe with help of advanced optical measuring system and high speed camera.
Intermediate crack (IC) induced debonding failure of fibre reinforced polymer (FRP) plate strengthened reinforced concrete (RC) beams is one of the common debonding modes, in which debonding initiates at a major flexural crack and then propagates toward a plate end. Finite element (FE) method has...
This paper performs a statistical analysis of previously proposed models for resisting the debonding of FRP sheets used in strengthening reinforced and prestressed concrete beams. End debonding and intermediate crack-induced debonding modes of failure are studied for beams in flexure. Two differe...
The crack pattern in a strengthened concrete member differs from that in a traditional reinforced concrete member. Generally, average crack spacing and width in strengthened concrete is dependent on strengthening factors other than the rebar. Therefore, it is difficult to determine actual crack w...
This paper presents experimental and numerical investigations about the fire behaviour of reinforced concrete (RC) beams flexurally strengthened with carbon fibre reinforced polymer (CFRP) laminates. The main objective was to assess the efficacy of different fire protection systems and to evaluat...
submitted by laesboptesto2270 2 years and 1 month ago
The effect of pre-intermediate separation on the flexural behavior of strengthened steel-concrete composite beams by either adhesively bonded carbon fiber reinforced polymers (CFRP) sheet or welded/bonded steel plate was studied. In the case of strengthened by CFRP sheet, two different attachment...
A spectral method is proposed for solving static and dynamic problems in FRP-strengthened reinforced concrete beams in a unified way. In order to appropriately simulate the debonding failure a mechanical model considering non-linear stress-strain relationships for concrete and steel is used. The ...
A numerical model is developed to predict the behavior of castellated beams with hexagonal and octagonal openings up to failure. The numerical model takes into account both material and geometric nonlinearities. To initiate buckling, an initial small out-of-plane geometric imperfection, obtained ...
To assess the effectiveness of the near surface mounted (NSM) technique, in terms of load carrying and moment redistribution capacities, for the flexural strengthening of continuous reinforced concrete (RC) slabs, an experimental program was carried out. The experimental program is composed of th...
Recent experimental research has shown that the Near Surface Mounted (NSM) technique has significant potential for increasing the load-carrying capacity of continuous reinforced concrete (RC) slabs. This flexural strengthening technique is based on the installation of rectangular cross sectional ...
We report on a new experimental setup for the investigation of proton induced reactions on exotic nuclei in inverse kinematics. It was installed and successfully used in the scattering study of intermediate-energy protons (∼700 MeV/u) on neutron-rich nuclei 6,8He produced with the FRagment Sepa...
