Modelling of concrete beams reinforced with FRP re-bars

A finite element analysis of reinforced concrete beams with fiber-reinforced plastic rebars is performed. Corrosion of steel re-bars is a common problem encountered in the civil construction sector, due to the porosity of concrete. The use of fiber-reinforced polymers (FRP) instead of steel re-bars can lead to a better corrosion-resistant reinforced concrete with applications in many construction fields. The need for nonlinear geometrical and material models implies the use of numerical methods such as the finite element method. In this paper the use of a first-order shear-deformation theory in the analysis of concrete shells reinforced with internal composite unidirectional rebars is proposed. The theory is implemented in a shell element that allows for a layered discretization of the laminate materials. A perfect plastic and a strain-hardening plasticity approach are used to model the compressive behavior of the concrete. A dual criterion for yielding and crushing in terms of stresses and strains is considered, which is complemented by a tension cut-off representation. The material law for the unidirectional re-bars is linear elastic/brittle, whereas the concrete allows for elastoplastic¯brittle behavior. A simply-supported concrete beam, reinforced with composite re-bars is analysed. The effects of the reinforcement and the comparison of composite and steel re-bars on concrete are discussed. Comparison between numerical and experimental results is made for a RC beam reinforced with pultrusion rods.