A novel FE model for RC beams strengthened in bending by mechanically fastened FRP laminates

This paper proposes a Finite-Element model (FEM) for simulating the behaviour of RC beams strengthened by Mechanically Fastened FRP laminates (MF-FRP). The model is developed by assembling a frame-like element to simulate the RC beam, a “rod” element for the external FRP laminate and two springs to connect the above elements. Well-established stress-strain laws are considered for simulating the nonlinear behaviour of both RC beams and FRP laminates, while the force-slip relationship describing the behavior of the two springs is calibrated on the results of direct-shear tests on MF-FRP laminates performed by the authors and already published in other papers. The proposed FEM model is validated by comparing the numerical simulations with results of some experimental tests available in the literature