Flexural behaviour of multi-span GFRP-concrete hybrid beams

This paper presents results of an experimental and analytical study on the flexural behavior of multi-span GFRP-concrete hybrid beams. Previous investigations showed the viability and technical advantages of connecting GFRP pultruded profiles to concrete elements in GFRP-concrete hybrid cross-sections, used in simply supported structural elements. The objective of the present study was to investigate the flexural behaviour of the GFRP-concrete hybrid solution in continuous structural elements, in which, in addition to the lower deformability when compared to isostatic systems, the cross-sectional and structural redundancies may also allow for a certain pseudo-ductility at failure. With this purpose, a set of design equations was derived in order to analyse the flexural behaviour of continuous hybrid beams, subjected to positive and negative bending. Those equations were used to design two continuous 3-span and 2-span hybrid beams with a bonded shear connection system, which were tested in bending. The flexural tests allowed us to investigate the serviceability behaviour and the failure mechanisms of multi-span GFRP-concrete hybrid beams.