Finite element simulation and testing of ISW CFRP anchorage

Several Carbon Fibre Reinforced Polymers (CFRP) systems have been used successfully for strengthening of structures during the last decades. However, the fracture often occurs in the concrete adherent or in the adhesive interface when used for steel strengthening. As a consequence the CFRP is poorly utilized with a non ductile and brittle failure mode as the outcome. Mechanical anchorage can be used to utilize the full capacity of the CFRP materials but cannot yet challenge systems used for steel. Such systems can be used to transfer stresses from the CFRP material efficiently to the remaining structure. However, reaching the full capacity of the CFRP material is difficult since anchoring often courses premature failure modes such as crushing of the Fibre Reinforced Polymers (FRP), slip in the FRP and adjacent adherent, cutting of the fibres, bending of fibres and frontal overload. This paper presents a novel mechanical integrated sleeve wedge anchorage which seem very promising when perusing the scope of ultimate utilization of CFRP 8mm rods (with a tension capacity of approximately 140kN). Compression transverse to the CFRP is evaluated to prevent premature failure. The anchorage is modelled in the 3D finite Element program ABAQUS, just as digital image correlation (DIC) testing was performed to verify the finite element simulation. Also a new optimized design was produced to ensure that the finite element simulation and anchorage behaviour correlated well. It is seen that the simulation and DIC testing correspond well when strains on the barrel surface are compared. As a consequence it was possible to produce a new optimized anchorage which utilized the full capacity of the 8mm CFRP rod.