Torsional behavior of GFRP-RC pontoon decks with an edge cutout and diagonal reinforcements

Large-scale pontoon decks with edge cutouts were tested and the effect of diagonal reinforcements, arrangement of bars, and reinforcement-grid space size was investigated. The generated experimental data demonstrated the enhancement in the pre-cracking torsional behavior provided by diagonal reinforcement in double-layered reinforcement. Meanwhile, a further improvement in the reinforcement design with a denser grid spacing of 100 mm in double-layer mesh exhibited 137 % higher post-cracking torsional rigidity than that of the deck with a 250 mm grid spacing reinforcement. The former deck presented similar torsional behavior as the double-layered reinforced solid deck. The cracking torque and post-cracking torsional behavior of the pontoon decks can be accurately predicted with the introduced equations with consideration of the effective width related to the contribution of diagonal bars and considering the contribution of longitudinal GFRP bars, respectively.