Newmarket Viaduct

The viaduct was opened on 3 September 1966 at a cost of NZ$2.26 million, and was constructed as New Zealand's first pair of balanced cantilever bridges.

[1] With its long spans, the s-curvature and the varying superelevation of the motorway, it is a complex structure even today, and at the time was a ground-breaking design for New Zealand.

[5] Also, during design, temperature stresses were not yet understood to a sufficient degree, leading to cracking between the black bitumen coat and the light-coloured concrete beams below.

However, its structural elements did not lend themselves to easy strengthening, and even a reconditioned viaduct would only have provided an estimated life expectancy of 40–50 more years.

[1] The new Transit New Zealand structure was estimated to cost NZ$150 million, and cleared planning hurdles quicker than expected, leading to hopes that it would be possible to build it in time for the 2011 Rugby World Cup.

[9] Tonkin + Taylor and URS New Zealand, as part of the Northern Gateway Alliance, were assigned to develop the new bridge, and one of their design targets included full recycling of all material during the project.

[10] However, estimated costs in June 2008 had risen to NZ$187 million, and it was unclear whether the funds would be made accessible quickly enough to achieve the ambitious schedule of finishing the bridge in time for the 2011 World Cup.

[4] Some further urban design improvements were also part of the project, such as a volcanic-themed walkway from Gillies Avenue down towards Newmarket (connecting to Clovernook Road).