Transverse bending and in-plane shear behaviours of multicellular pultruded GFRP deck panels with snap-fit connections

This paper presents experimental and numerical investigations about the transverse bending and in-plane shear behaviours of pultruded bridge deck panels made of E-glass fiber reinforced polymer (GFRP). The analysed panels have a wide multicellular thin-walled cross-section, with panel-to-panel vertical interlocks (snap-fit) at the lateral edges. The study aimed at understanding and quantifying the structural contribution of the deck panels, in terms of their transverse stiffness and strength properties, w. r.t the load transmission to the lower support girder system along its longitudinal axis (bridge's main axis). Particular focus was given to the influence of the panel-to-panel joining system on the transverse performance of the deck when compared to a continuous panel (i.e. without snap-fit). The effects of complementing the snap-fit connection with two different structural adhesives was also investigated. For all deck configurations tested, the structural response in bending and shear exhibited high post-cracking strength and pseudo-ductility (above 100% and 200% respectively), as a consequence of the redundancy provided by the multi-cellular section. Compared to a continuous deck, the mechanical snap-fit exhibited very high deformability; however, when combined with adhesive bonding, it behaved fairly rigidly. In general, failure occurred in a progressive way (crack initiation and propagation) and the ultimate capacity was governed by the web-flange junctions. The numerical simulations, which were performed with continuum shell finite element (FE) models using Hashin-based damage analysis, provided useful insights about the failure mechanisms. Both bending and in-plane shear responses were simulated with good accuracy, with matrix tension failure governing the load capacity. The low value of the estimated in-plane shear modulus was consistent with the very low interaction degree (3–4%) that was assessed between the panels' flanges under bending, thus highlighting the high flexibility of this bridge deck's multicellular core when subjected to transverse loading.