Construction of the Waterview Connection's motorway-to-motorway interchange now extends over one of Auckland's busiest sections of highway, and the NZ Transport Agency advisers drivers of some night time disruption to complete the work safely.
Large concrete beams weighing between 60-69 tonnes and up to 36m long are being lifted into place above the Northwestern Motorway (State Highway 16) for the second of the four interchange ramps to link the Northwestern and Southwestern (SH20) motorways.
"The beams are lifted at night to minimise disruption, but for people's safety we do need to close the traffic lanes below when the beams are being placed into position," says the Transport Agency's Highway Manager, Brett Gliddon.
The closures currently affect the Northwestern Motorway westbound lanes between the off and on ramps at Great North Road. Next week, eastbound lanes will be closed between Great North Road and St Lukes.
The concrete beams are carried into place by a mobile lifting gantry similar to one used recently to construct the new Newmarket Viaduct on Auckland's Southern Motorway (SH1).
The yellow gantry – named Dennis to commemorate a project worker who died last year from cancer – travels on and above the ramps as it builds them.
"Using the mechanical muscle of Dennis as it works its way over the motorway at night has advantages for both the project and road users," Mr Gliddon says.
"Dennis eliminates the need to use conventional ground-based cranes that would need to be moved into place at the start of every shift and then taken away again. It saves time, reduces traffic disruption, and avoids the need to use those cranes in the environmentally sensitive areas of the Oakley Creek estuary."
During the day Dennis will remain perched above the Northwestern Motorway, but Mr Gliddon says the gantry will not be working then over live traffic lanes.
The total length of the four new interchange ramps is 1.7km. They are 20m aboveground at their highest point. The ramp now under construction will be used by Northwestern Motorway traffic from the west wanting to access the Waterview tunnels.
The first ramp, which was completed in May, is the one drivers will use from central Auckland to use the tunnels to reach Auckland International Airport and Auckland's south.
The interchange is one part of the Waterview Connection – New Zealand's largest ever road transport project which also includes construction of two three-lane tunnels 2.4kms long. The project is part of Auckland's Western Ring Route, one of the Government's flagship Roads Of National Significance (RONS). When completed, the Western Ring Route will be a 47 kilometre-long motorway between Albany on the North Shore, around the top of the Waitemata Harbour, and Manukau in the city's south.
The Transport Agency says it plans to open the Waterview tunnels and interchange in early 2017, providing drivers with seamless travel in all directions between the Northwestern and Southwestern Motorways.
The Waterview Connection project is being delivered by the Well-Connected Alliance which includes the Transport Agency, Fletcher Construction, McConnell Dowell, Parsons Brinckerhoff, Beca Infrastructure, Tonkin & Taylor and Japanese construction company Obayashi Corporation. Sub-alliance partners are Auckland-based Wilson Tunnelling and Spanish tunnel controls specialists SICE.