This contract was tendered to the Whangarei District Council for the construction of a new walking bridge on a recreational walking track at Tutukaka, Whangarei. The bridge was an 11.0m timber structure to bridge an unsafe gap where pedestrians had to scale part of a steep bank to otherwise get around it.
The major challenge involved with this project was the access, the project was on an isolated bank on the water’s edge only accessible by a largely incomplete walking track or by boat. The access track was referred to by our staff as a ‘goats track.’ Getting materials to the construction site was a huge challenge. Due to the fact we were working in a marine tidal environment, a large proportion of the materials were transported to the site by use of a small boat. This meant on some occasions we were limited to what days & hours we could work as tide levels would often restrict the accessibility of the structure. To get the poles onto the site, we had to use a helicopter to lift them from the nearby marina car park area. We also worked from a boat to do some of the work underneath the bridge & used the boat to bring in some of the materials.
The innovative part of the project was the alternative design offered for the project to core and grout anchor bars 1500 mm into the bedrock at each end of the bridge in lieu of the abutment piles required whilst still satisfying the engineers structural requirements. This meant we did not need to establish a barge or piling equipment, saving significant cost to the client. Also, using the helicopter to lift the poles into position and land them on the abutments was an innovation that saved us significant time and risk of trying to transport the poles to site using marine equipment.