The Harewood Underpass was built as part of the $93m Early Contractor Involvement (ECI) Russley Road Upgrade for the New Zealand Transport Agency (NZTA). The Underpass is 180m long, including ramps leading to an 80m enclosed section passing under the roundabout at the intersection of Russley and Harewood Roads in Christchurch. It opened to the public on 9 September 2016; two months early.
The new underpass is intended to deliver a piece of infrastructure that celebrates pedestrian and cycle travel, encouraging more movements and setting a trend for high quality active transport infrastructure in Canterbury. It will provide safe passage for pedestrians and cyclists under the new Harewood Roundabout and to the growing Christchurch International Airport precinct.
The Underpass panels are cast using concrete moulds following a 3D CAD model to achieve a smooth and accurate finish. They are painted glossy white and respond to the white facetted forms of the snowy Southern Alps backdrop. The inter-panel sections were cast in-situ using vertical rough sawn timber boards with vertical 10mm triangular grooves to contrast with the texture and form of the precast panels. These are painted in the colours of the sky from west to east: West Coast sunset, stormy West Coast sky, the NW arch and the broad blue Canterbury sky.
Within the roundabout section 25 spun, 500mm diameter concrete pipes bring natural light into the middle of the underpass, providing a connection with the environment. They are oriented towards the sun to deliver moments of sunlight that travel along the walls and floor as the sun moves in the sky. These are painted in the same high gloss white to reflect natural light into the Underpass.
Sustainability was linked throughout the build via the reuse of temporary works, and recycling of material from the excavation and the road area within the roundabout. The design encouraged the use of recycled secondary aggregates in all the concrete mixes, while precast construction provided an efficient use of panel moulds and a very productive construction method.
The quality of the finished structure is supreme and sets a very high standard in urban transportation features for the future. The completed structure will become a “must use “ facility as it is a striking, aesthetic, functional cycle way, beautiful in its context, finishes, features, colours and of superb quality. Indeed, concrete at its very best!
Taken from Concrete magazine.