Glass fibre reinforced polymer (GFRP) composites are currently being used as reinforcing bars in concrete and hybrid structures. An appropriate characterization of GFRP bars for concrete reinforcement is required by the structural designers prior to their use in structural applications. An extensive experimental program has been carried-out and the test results obtained from tensile tests on samples made of glass fibres and vinyl ester resins are presented and analysed in the paper.

The experimental tests have been accompanied by a numerical modelling performed to characterize the stress field in the bar ends and along the test portion of the specimens.

Three sets of 10 bars with diameters 8, 12 and 16 mm have been tested in tension, determining the ultimate tensile strength, the elastic longitudinal modulus and the ultimate tensile strain.

The experimental results are in line with similar work carried out by other research teams. It has been found out that the experimental procedure and the accompanying numerical modelling provide an adequate characterization of the GFRP bars giving the main properties needed for design.