Proposal of the concrete-GFRP interaction models

The results of an extensive experimental program aimed at understanding the structural performance of composite elements made of fiber-reinforced composite materials (fiber-reinforced polymers, FRPs) and concrete (C) are presented in this paper. The tests were carried out on pultruded unidimensional elements (beams and columns) made of glass fibers embedded in a hot-hardening vinyl-ether resin matrix, GFRP (glass fiber-reinforced polymers). These elements were coupled to concrete by means of either structural glues (based on polymeric resins). The constitutive law of the C-GFRP interface, with/without a structural glue, (a) was formulated on the basis of some specific experimental results, and (b) was instrumental in modeling the composite structural members, including their mutual mechanical interaction. On the whole, substantial agreement was found between the experimental and numerical results, this being a demonstration of the soundness of the proposed interface model that was implemented into an off-the-shelf FE code for nonlinear analysis, where each material of the composite members was independently modeled by means of six-node isoparametric brick elements.