8 | REGIONAL DEVELOPMENT McConnell Dowell: Ngā Hau Mangere Bridge T T Richard Loader Distinctive bridge connects communities Ngā Hau Māngere makes an iconic landmark across the water. Elegant, complex and with a distinctive central arch curving outwards from one side, Ngā Hau Māngere Bridge is designed for pedestrians, cyclists, and recreational fishing, and reconnects the communities of Onehunga and Māngere. Spanning 260 metres across the Manukau Harbour, Ngā Hau Māngere replaces the much-loved old Māngere Bridge which was closed in 2018 for safety reasons after serving the community for over a century. Ngā Hau Māngere’s wide deck varies between eight and twelve metres, allowing walkers and cyclists to safely travel between Māngere and Onehunga, while providing places for the community to sit and enjoy the surrounding harbour and landscape. Two dedicated bays, complete with stainless steel rod holders, support fishing and other recreational activities. The crown jewel of the bridge is a dramatic 60-metre steel-tied central arch, that sits on a central steel deck, and curves away from the (now removed) old bridge. Strong collaboration with local iwi / mana whenua resulted in key architectural features including pre-cast concrete panels on the side of the bridge that display a ‘puhoro’ pattern (representing a waka moving through water), and handrailing that transitions from light blue to turquoise to dark blue to beige and then to a pink, reflecting colours of the kahawai fish. Two pre-cast concrete Pou eight metres tall are currently being constructed at either end of the bridge, and the treasured historical legacy is maintained by artefacts from the old bridge included in a heritage garden on the Onehunga side. Lit up at night, Ngā Hau Māngere makes an iconic landmark across the water. Funded by NZ Transport Agency Waka Kotahi (NZTA), and designed by international design consultants Aurecon, McConnell Dowell were awarded the contract to build the new bridge including the design and coordination of all temporary works (to facilitate the construction of the new bridge) and demolition of the old bridge. Construction of the new bridge commenced in September 2019, with completion achieved in August 2022. David Pattinson, McConnel Dowell’s Project Manager who had responsibility for Ngā Hau Māngere at its completion, says it was the most complex structure he had ever been involved in over his forty-year career. “It was a most rewarding project to have been involved in. The temporary works that had to be undertaken to build the bridge were absolute next level, but none of that is seen in the finished bridge.” Bored concrete piles on the harbour bed formed the foundations that the new bridge was built upon. On top of that there was a huge concrete pile cap supporting the piers, explains David. “Prior to any construction work commencing, a temporary steel trestle, with wooden deck, was constructed. It was located ten metres away and parallel with the new bridge and provided access for cranes and materials to each of the new piers, and for demolition of the old bridge. “For each individual pier, a steel sheet cofferdam was driven into the harbour bed, sea water pumped out the from inside, providing access to a dry seabed to construct the foundations. The cranes sitting on the temporary trestle structure were located directly under high voltage power lines and so any steel sheet or pile that was driven into the seabed had to be installed in two halves and welded together to avoid contact with the power lines. “Furthermore, for removal of much of the temporary works, we had to put flotation buoys on them, drop them into the harbour below, then tow them out to the side whereupon they were lifted out with the crane. So, there were some incredible temporary works carried out.” Since its completion, Ngā Hau Māngere, and key project partners including McConnell Dowell, Aurecon, Bossley Architects and NZTA have been recognised at many national and international industry awards. In 2023, McConnell Dowell won Category D (projects between Warkworth and Pokeno valued between $20 million and $50 million) in the Auckland regional CCNZ Hynds Construction awards and went on to be voted Supreme winner by industry peers. “This was industry peers voting for you, so it was fantastic,” says David. “ Everybody just leapt out of their seats, it was such a wonderful achievement by everybody involved in the project, and testimony to the incredible effort put in by the team.” Invercargill l Christchurch l Nelson l Manukau l Hamilton l Hawkes Bay l North Shore 0800 365 4322 www.advancedpersonnel.co.nz Proud to support McConnell Dowell Connecting the best people with the right business. ALRITE STEEL & SERVICES NZ LTD YOUR NEW ZEALAND STEEL DISTRIBUTOR Alrite Steel are passionate about supplying high quality, cost effective and compliant steel products throughout New Zealand and the Pacific Islands. With a combined experience in 80 years of industry knowledge, Alrite Steel is your New Zealand Steel Distributor. www.alrite.co.nz 09 270 2008 info@alrite.co.nz
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