SkyPath - A light weight FRP solution adding capacity to an existing highly loaded bridge

This paper will summarise the key design features of a project that has utilised light weight modern composite FRP materials to reduce load demand on an already highly loaded existing bridge structure, allowing the addition of pedestrian and cycle access to a main arterial harbour crossing in Auckland.

For the last decade, a dedicated and passionate team, including engineers and architects, has worked to create a viable option for a pedestrian-cycle way across the Auckland Harbour Bridge. There were many engineering challenges to overcome from understanding that the existing one-kilometre structure was already nearing maximum loadings.

During that time steel and aluminium solutions were developed that would attach to the bridge at 4.5m frame spacing and be made up of 160 x 7m long modules which would provide a 4m wide, 1 kilometre long pathway to connect the Central City with the North Shore. Issues remained however around the added mass of the walkway, which would require significant stiffening of the main structure.

Gurit Asia Pacific and Core Builders Composites worked with the SkyPath team to develop an alternative FRP composite construction solution for the walkway modules thus addressing the issues surrounding adding self-weight to the existing bridge.