Structural Behaviour of Post-tensioned Pre-cast Segmental Decks for Flood Resilient Pontoons

Structural Behaviour of Post-tensioned Pre-cast Segmental Decks for Flood Resilient Pontoons

This thesis evaluates the structural performance of segmental concrete decks reinforced and post-tensioned with glass fibre-reinforced polymer (GFRP) rods. The segmental deck design offers significant advantages, such as ease of handling, transportation, and on-site installation, and promotes flexibility in future maintenance and replacement. In total, there are five research studies in this thesis. The first study experimentally and numerically evaluated the flexural behaviour of the GFRP-reinforced monolithic concrete deck. The influence of the cutout, loading type, span-to-depth ratio, and reinforcement-effective depth has been explored. In the second study, segmental decks with and without a gap in the joint and joined by handtight GFRP rods are tested under flexural-shear and shear loading. The gaps in the joint were found to negatively impact the flexural performance of the segmental plank, reducing the flexural stiffness and load-carrying capacity by 37% and 23%, respectively. In the third study, six large-scale post-tensioned segmental decks were tested in the flatwise and edgewise orientations under static flexural loading. The results showed that post-tensioning the GFRP rods improves the flexural performance of the segmental decks. In the fourth study, the shear behaviour of the segmental decks was investigated by applying the load to the joint. It was found that post-tensioning of 7.4% of the rod's ultimate tensile strength reduced the self-weight deflection by 92% and increased initial stiffness by 8.7 times compared to segmental decks without prestressing. The last study evaluated the structural behaviour of the segmental deck under cyclic loading. By applying pre-compression stress of 1 MPa, the segmental precast concrete decks can achieve more than 1,000,000 fatigue cycles without any failure, but only a slight GFRP rod axial load relaxation. The outcome of this thesis provided a better understanding of the static and cyclic behaviour of the GFRP-reinforced segmental and monolithic concrete decks, offering a more reliable, durable, and cost-effective construction system for constructing marine infrastructure.

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