A new sculptural underpass located under a large roundabout on SH1 Harewood and Russley Roads in Christchurch is creating quite a stir. The peaks and troughs of the jagged design depict the mountain peaks and valleys of the Southern Alps and, incredibly, are formed from concrete precast panels.
The unique art-like feature was commissioned by the NZ Transport Agency, designed by Aecom and Jasmax and constructed by McConnell Dowell - Downer Joint Venture. At the entrance of the underpass panels of rough timber provide variation and colour to the white, angular walled space. A series of skylights brings both natural light and air into the roomy underpass.
“In the beginning we had lots of discussions with Campbell and the CanCast team (the precast concrete manufacturer given the job of creating the walls to the underpass) and we had quite a design overhaul which meant we moved away from 2m culverts to the larger 6m panels,” explains Ryan Hickey, Project Engineer for McConnell Dowell - Downer Joint Venture. “Working with the CanCast team in the early stages meant we could maximise the advantages of precasting, so we could provide the most efficient system to construct the walls, within a difficult construction site.”
“Once the construction method was settled on, the pattern to create the panels was supplied to us by McConnell Dowell – Downer JV,” explains Campbell Parton, Production Manager for Cancast Ltd. “We constructed the moulds around the Aecom/Jasmax design and Firth came to the party by supplying a purpose made 40MPa mix.”
Campbell explains that once he had the concrete moulds formed he then worked with the Firth technical guys to get the slump just right to ensure a consistency of finish - suitable for paint - to the panels.
There are three sections to the tunnel - the Northern end, the Southern end and the wing walls - with each panel designed to ensure those passing through are reminded of the nearby mountains, with the tussock plantings at the entrances continuing this theme.
Campbell and his team also produced the roof panels which required diagonal voids for the inclusion of sky lights and LED lighting.
“We are very pleased with the final outcome,” adds Campbell. “It looks amazing. The combined effort of the designers, the McConnell Dowell and Downer team, ourselves and Firth has produced quite a feature. We get all our concrete through Firth and have worked with them for years. We have a great relationship and trust their expertise when it’s required. We wouldn't use anyone else.”
The 100-metre underpass links the airport with the city and also forms part of the Christchurch cycle network which aims to increase cycling movements threefold by 2041.
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The visually striking structure has won recognition with the NZILA Award of Excellence – Infrastructure for Jasmax at the Resene NZILA Pride of Place Landscape Awards. The NZ Transport Agency’s Harewood / Russley Road underpass is part of the Government’s Roads of National Significance $112 million Russley Road Upgrade, part of the wider $300 - $350 million Christchurch Western Corridor Upgrade. |
Principal: NZ Transport Agency
Main contractor: McConnell Dowell and Downer Joint Venture
Customer: CanCast Ltd
Location: Harewood Underpass, Christchurch
Product: Certified Concrete®
