Modelling of concrete beams reinforced with FRP re-bars

Abstract

A finite element analysis of reinforced concrete beams with fiber-reinforced plastic re-bars 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 non-linear 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 re-bars 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 elasto-plastic–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.