Drilling of about 1400 holes takes place on the Main Breakwater wave wall for steel strengthening and connection points. Photo: Supplied
- Main breakwater wave wall was constructed in 1994
- 5m tall and 170m long
- It was damaged in weather events in 2005 and 2022
- Seven 15-tonne steel reinforced panels are being installed
- 1400 holes have been drilled into the wall for steel strengthening connection points
- Project to take three months
Port Taranaki is strengthening the wave wall of its main breakwater to better protect vessels and people and help prepare the port for future trade opportunities.
The main breakwater shields the port from the prevailing westerly winds and currents of the open sea. The concrete wave wall, which is five metres tall and stretches 170m, provides added protection for the vessels moored on the breakwater berths and the nearby Moturoa Wharf.
Project manager Dougal Morris said like the breakwater, the wave wall dissipated the power of large waves that hit the breakwater.
"It was constructed in 1994, and since then two sections have been damaged during storm events - a number of panels were replaced following a 2005 event, and several panels were damaged during ex-tropical Cyclone Dovi in 2022."
Steel rods are in place for the concrete footing and the tapered concrete reinforcing wall on the 1994 section of the Main Breakwater wave wall. Photo: Supplied
Following an assessment of the wall following Cyclone Dovi, work was being undertaken to replace seven panels and further strengthen the 1994 section.
The seven, 15-tonne steel reinforced concrete panels had been locally engineer-designed and precast off-site in Taranaki. Each was five metres tall, three metres long and 450mm at the base, tapering up to the top where a 700mm thick lip minimised wave spray over the top.
The panels were being trucked to site and lifted by crane into place, interlocking together to improve rigidity.
The concrete footing and tapered concrete reinforcing wall begin to take shape. Photo: Supplied
Morris said six of the panels being replaced were at the extreme eastern end of the wave wall, with the other being the first of the wave wall, closest to the port.
"The first and last panels of a wave wall are very important, as each needs to be strong to help maintain the integrity of the wall. If either end panel fails then it creates a cascade effect."
The concrete footing and tapered concrete reinforcing wall begin to take shape. Photo: Supplied
To prevent this occurring, a metre-thick and 3.8m tall buttress was being installed at each end of the wave wall. A concrete footing more than a metre deep and 600mm high was being poured along the length of the wave wall on the breakwater side to provide added strength at the base.
"We're also adding a supporting length of tapered reinforced concrete wall on the breakwater side of the 1994 section. It reaches about 2.4m up the existing wall and is connected to the wall via a number of steel rods.
"All up, about 1400 holes have been drilled into the wall and the wharf for steel strengthening and connection points."
The three-month project involved several local contractors and port teams.
The first of seven, 15-tonne reinforced concrete replacement panels is lifted by a Port Taranaki mobile harbour crane. Photo: Supplied
General manager infrastructure John Maxwell said the often turbulent conditions on the West Coast caused wear and tear to the breakwaters and wharves, and the port invested annually in repairs and maintenance.
"Our priority is providing a safe harbour for our customers, their people, and assets, and for our vessel fleet and people, so ensuring our wharves and breakwaters are operating effectively is extremely important."
The first replacement panel – the first panel of the Main Breakwater wave wall – is put in place. Photo: Supplied
Maxwell said the strengthening work had a long-term focus.
"We're looking ahead to the future of Port Taranaki and our role in possible trade and energy opportunities, such as supporting an offshore wind industry and [oil and gas] decommissioning projects.
"Our port may change and adapt to new trade, so potential customers will want to know that their assets, infrastructure and people will be protected as best as possible. Therefore, having a high-strength engineered breakwater and wave wall is imperative."
Panels at the eastern end of the wave wall are put in place. Photo: Supplied
Maxwell said in addition, with climate change-related weather events expected to increase in frequency and strength, future-proofing and mitigating climate-related risks was important.
"This work helps to ensure and maintain the supply chain so that our customers and potential customers can continue to safely trade through our port, both now and in the future."
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