Flexural behaviour of GFRP-reinforced concrete pontoon decks under static four-point and uniform loads

Concrete pontoon decks are subject to flexural loading actions under concentrated and uniform loads caused by self-weight, live loads, and wave actions. This study investigated the structural behaviour of concrete pontoon decks reinforced with glass fiber-reinforced polymer (GFRP) bars under static four-point and uniform loading conditions. Five large-scale GFRP-reinforced concrete decks with a length of 2400 mm, width of 1500 mm, and thickness of 125 mm were tested to evaluate their moment capacity, strain behaviour, cracking propagation, and failure mechanism. The effects of the loading configurations, reinforcement arrangement, and cutout simulating the piles' location were evaluated. The edge cut-out initiated flexural-shear cracks, causing the pontoon decks to fail at an effective bending stress 10% lower than the solid decks. Decreasing the span-to-depth ratio from 5.6 to 4.0 increased the induced shear stress of a section and caused the deck to fail by shear compression. Uniform loading resulted in an even load distribution and minimized the stress concentration around the cutout. An increase in the effective depth improved all deck flexural characteristics. The equations in ACI 4401. R-15 and CSA S806-12 provided an accurate prediction for solid decks but overestimated the ultimate flexural strength of the GFRP-reinforced concrete decks with a cutout.