Load response due to local and global indeterminacies of FRP-deck bridges

In a cellular FRP deck-on-beam bridge, the deck’s load response is influenced by the cellular frame’s local indeterminacy and by the global indeterminacy due to multiple beams at each support. Thus, the stiffness distributions for both levels of indeterminacy are important. This paper reports concentrated load tests and FE analyses (FEA) of an 8 m long bridge comprising cellular FRP decking bonded to and spanning across three pretensioned concrete beams. Another specimen comprising a rigidly supported, narrow width of decking where only local strains developed under load and which enabled strain measurements near the loads on external and internal surfaces of the deck, is also presented. Loads were applied via steel plates and elastomeric pads. Pressure-sensitive films enabled deduction of pad-to-deck contact zones. The FEA used contact elements at pad–deck interfaces, solid elements for the deck and beams, and included deck material and geometry anisotropies. The bridge’s test data show a 25% asymmetry of the deck’s local longitudinal strains and rapid transverse attenuation of these strains away from the loads. The FE results – including the strain asymmetry when FRP moduli are locally altered – are comparable to the experimental data. This suggests that FEA can reliably represent indeterminacy effects for these complex structures.