Waterway Constructions, a Keller company, has completed a pier upgrade on Norfolk Island, off the east coast of Australia.
The project on the 35km² island, which sits 1400km off the coast of Australia in the South Pacific, involved extending a pier on the north-east coast by 25m, raising it 1m and constructing a 1m high wave-deflector wall. The scope also included installing a new 35t dock crane.
In early 2016, Waterway Constructions won the AUS$15M (£8.53M) contract from the Australian government to upgrade one of the island’s two piers. The aim was to better service fishing and cargo boats, as well as improving accessibility for cruise ships to boost the local economy.
The pier construction involved using precast units, fixed to the seabed with ground anchors that were installed by Keller Australia.
The units were then mass filled with rock and then grouted to form a completely anchored mass structure. All concrete was reinforced with stainless steel reinforcement bars.
Waterway Constructions northern region operations manager Tony Matthews: “There was a lot of careful planning beforehand, with everything needing to be ordered well in advance because of a six-week transit time from the mainland.
“We shipped over all our diving gear and drilling equipment, and were able to use the island’s excavators, but we needed to import a 25t capacity crane to assist in undertaking the works.
“All cargo coming to the island was transferred from the cargo ship, which was moored offshore, to the pier via timber boats (called lighters). These boats had limits on the size and weight of items that could be transferred. Therefore, we asked the crane manufacturer to completely strip down the crane – wheels, axels, counter weights, boom, engine, everything – ship it to the island, then rebuild it and retest it ready for the job.”
The team also couldn’t import any readymade concrete, so the crew – which included trained locals working with the Waterway team, had to source and produce their own aggregates from the island.
“We brought in a concrete technologist to create the 40mpa concrete we needed,” adds Matthews. “We had to make sure all the batches were consistent, so we spent around three months carefully developing and testing mixes, which involved sending samples to a lab back on the mainland.”
During construction the temporary works was designed to withstand the 5m high waves and four major swells from passing cyclones – each typically resulting in a week’s lost construction time.
“We built in a 32-day weather contingency based on historical data,” Matthews says. “But the conditions were particularly bad during the second half of the project and in the end we used all of that time plus an additional 46 days. At all times, though, there was huge emphasis on safety, and all the local workers were trained and very closely supervised.”