Non-linear FE Modelling of CFRP-strengthened RC Slabs under Cyclic Loading

The nonlinear behaviour of an adhesive layer connecting carbon fibre reinforced polymer (CFRP) to reinforced concrete one way slabs is numerically simulated in the current study. This investigation is aimed at developing as well as validating a threedimensional finite element model. Numerical results have been compared with those obtained from an earlier experimental study. The FE model was then subjected to the modified fatigue load protocol recommended by FEMA 461. A detailed and accurate 3D FE model of the composite one-way slab was developed using ABAQUS software. A non-linear damage plasticity model is considered for modelling the concrete, and the FE model accounted for the nonlinearity of the concrete under cyclic loading by estimating the stiffness degradation in the concrete for both compression and tension effects. A surface cohesive based model was used to describe the interaction between the CFRP and the concrete slab. For the reinforcement bars, the Bauschinger effect was adopted through the application of the kinematic hardening model under cyclic loading. The FE model was then validated by comparing numerical and experimental values for load-deflection, load-strain in CFRP and load-strain in embedded reinforcement bars. Furthermore, the strain profile of CFRP, slip at interface in monotonic and cyclic loading, and both reduction in the ultimate load and stiffness due to cyclic loading were observed in this study.