Flexural behaviour of the segmental precast concrete decks post-tensioned by GFRP rods

This paper introduces an innovative post-tensioned segmental concrete deck system internally reinforced and tied with GFRP reinforcements for application in pontoon decks and other deck structures in aggressive marine environments. Utilisation of the GFRP reinforcements in floating concrete structures is essential because of their non-corrosive characteristics. Six large-scale segmental decks following the specifications of Queensland maritime infrastructure were designed, manufactured, and tested to assess the reliability of the new construction system under static flexural loading in the flatwise and edgewise orientations. One segmental deck served as a reference with hand-tight post-tensioning, while the remaining specimens were connected by the GFRP rods with varying levels of post-tensioning. All decks were tested up to failure, allowing for an investigation of their flexural strength, load-strain behaviour, joint opening, and failure mechanism. The results showed that posttensioning the GFRP rods improves the flexural performance of the segmental decks. The higher the level of post-tensioning, the higher the contact area between the segments at the joint is achieved. A numerical model was developed to understand the detailed mechanism of both flatwise and edgewise specimens. A strain reduction coefficient in the segmental concrete deck under flexure is introduced accounting for the joint presence to reliably calculate the stress in the post-tensioned internal GFRP rod when the concrete in the joint crushes. The system investigated can increase maritime and recreational infrastructure's construction efficiency and provide creative solutions in the GFRP-reinforced concrete structures in the building and construction industry.