Category 4: Projects with a value greater than $100 million
Winner: Well-Connected Alliance – Waterview Connection
The five kilometre Waterview Connection is to date the largest and most complex road infrastructure project undertaken in this country. The most significant feature is the two tunnels which are the longest road tunnels in the country.
Feasibility work started in 2000 with geotechnical investigations undertaken in 2008. Following a period of consultations, consents and financing, the design and construction was awarded to the Well-Connected Alliance* in late 2011, with construction commencing in early 2012. It opened to traffic in July this year.
The two, 2.4 kilometre tunnels are each three lanes wide, with an outside diameter of 14.41 metes and were constructed using a specially designed German tunnel boring machine (TBM) which bored at a rate of eight centimetres a minute under densely populated residential suburbs, a number of roads and the western rail corridor at a depth of 45 metres through a variety of ground materials, including hard rock. Some 800,000 cubic metres of rock and soil was excavated.
As the tunnels progressed, precast concrete ‘rings’ were attached to the wall to form the lining facia, with each ring being two-metres wide and weighing 10.5 tonnes.
The tunnels are equipped with the very latest in operating systems to ensure fire and safety regulations are met – including 4000 lights, 62 ventilation fans, 400 kilometres of cabling, and five deluge storage tanks each holding 250,000 litres of water.
Along with the road paving, tunnel entry/exit portals were constructed at each end, and a large interchange at the northern end links with the Northwestern Motorway.
The programming, sequencing and logistical work involved in the project was considerable and required significant planning and foresight. The major tasks were carefully monitored and managed on a critical path, each with the significant risks noted.
Taking just over five years to complete, the Alliance worked diligently to deliver this complex project to an extremely high standard and set the bar throughout the cycle of consultation, design and construction.
The completed project forms the ‘final link’ to connect two of Auckland’s busiest highways – the Northwestern (SH16) and Southwestern (SH20) Motorways and is an integral part of the city’s Western Ring Route.