Business North November 2021

48 | HEB Construction - Mount Maunganui: Opotiki Harbour Development Habour development taking shape Karen Phelps HEB Construction’s experience in delivering complex projects helped while working on the Opotiki Harbour Development Project. REGIONAL DEVELOPMENT 0800 WAIOTAHI For all your aggregate requirements. THE BAY’S FINEST CHIP SHOP. Waiotahi own and operate four Bay of Plenty Quarries where we are able to mix the finest raw materials to supply high quality products.  High PSV Sealing Chip  Sealing Chip  NZTA complying aggregate  Rip Rap and Gabion Stone  Road Aggregates  Screened River Run  Clay and Pumice  Washed Aggregates  Drainage Metals  Rotten Rock and Forestry Rock W orking in a marine environment out on the ocean, HEB Construction’s experience in delivering complex projects has stood it in good stead for working on the Opotiki Harbour Development Project, says HEB Construction project manager David Wyeth. It’s an important project for the region and the company has been involved since the outset, offering strategic advice on construc- tion issues to Opotiki District Council before the project was even put out to tender. Construction works commenced in September 2020 and HEB Construction is now 75% of the way through pouring the concrete armour hanbar units, which will form the outer layer of the two breakwater structures totalling 400 metres and 450 metres in length. In-between these two structures will be an approximate 120 metre dredged channel. David says coordination of the masses of rock needed for the breakwater structures has been a huge challenge, particularly as the project storage site is limited. Four quarries are delivering product of varying grades of rock. This has to be closely monitored to ensure adequate supply volumes are able to meet project deadlines, delivered at the right time to avoid clogging up the work site. He says this has required careful planning and a precisely thought out methodology, especially considering the breakwaters are constructed in the ocean with the team having to deal with constantly breaking waves. “To do this we’ve broken the breakwaters into cells. We drive sheet piles down one side to deflect the waves allowing us to work,” explains David. Part of this process has been assisted by a huge Liebherr crane, which was delivered to the site mid September. With a lifting capacity of 200 tonnes the crane has nearly 1000 horsepower and can be rigged with a maxi- mum of 80 metres of boom. It is the dynamic compaction feature of the crane that will be mainly used on the project. It will also help with installing sheet piles and placing concrete hanbar units. “The crane can drop a 30 tonne weight from 30 metres in a matter of seconds rather than minutes. “A very handy feature when you have to drop the weight thousands of times over the course of the project to compact the sands under the sea bed, which are prone to lique- faction in the event of an earthquake.” Opotiki’s harbour was once an important part of the district’s transport infrastructure providing a vital link to markets around New Zealand and internationally. As the region’s roading infrastructure developed, use of the port reduced and the harbour was not maintained. The Opotiki Harbour Development Project will see the construction of two sea walls either side of a new channel dredged to a depth of about four metres, then the closing of the existing river mouth. The Opotiki District Council and Central Government are