These include widening almost 9km of the Northwestern from St Lukes to Te Atatu, while raising the 4.8km motorway causeway across an inlet of the Waitemata Harbour and Whau River.
Motorway interchanges are being upgraded at Lincoln Rd in Henderson and at Te Atatu, to be followed soon by a duplication of the St Lukes Rd bridge over the Northwestern at Western Springs.
Waterview Connection
Link between Southwestern and Northwestern Motorways
Length: 4.8km (half of it tunnelled)
Cost: $1.4 billion
Completion: early 2017
Waterview components
Twin tunnels
Three lanes in each direction
A tunnel boring machine had by yesterday dug 744m of its 2.4km way north to Waterview, from where it is due to break out of the ground in September, before being turned around to burrow back to Owairaka. It is being tailed all the way by an enclosed conveyor belt which has removed about 122,000cum of soil to a drying plant. The machine has lined the tunnel with about 368 pre-cast concrete rings, to a maximum depth so far of 34 metres.
1. Southern end of tunnels
Photo / Richard Robinson
2km of surface road is being developed through Alan Wood Reserve and Hendon Park from the end of the Southwestern Motorway at Maioro St, New Windsor, where an interchange is being enlarged to feed traffic to and from the new tunnels, under the new Richardson Rd bridge.
The road sinks into a deep trench, from which the $54 million boring machine began its journey in November.
Six southern spans have been erected for a footbridge over the surface motorway section in Hendon Park.
2. Northern end
Photo / Richard Robinson
Excavation of a 25m-deep exit and approach trench has almost finished, and base slabs are being laid.
Large portal frames are being formed, ready for the boring machine to pop out of the ground in September.
Preparations for building a traffic emissions venting tower 120m on the other side of Great North Rd from the tunnels have been completed, and piling for the15m structure has begun.
Great North Rd has been looped for the first half of the tower before the road is straightened temporarily to make way for the boring machine, and then rediverted to complete the tower.
3. Waterview interchange
Photo / Richard Robinson
A big yellow gantry is installing beams over Great North Rd's approach to its existing interchange with the Northwestern Motorway, to form one of four new ramps feeding traffic in and out of the tunnels.
A large earth embankment has already been formed to carry traffic between the ramps and tunnels.
Large retaining wallsare being built from the future interchange to the east of the Carrington Rd bridge over the Northwestern Motorway.
4. Northwestern Motorway causeway
Photo / Richard Robinson
Length 4.8km
Cost $220million
Completion 2017
Causeway being widened and raised by 1.5m to provide extra traffic lanes and prevent flooding and to stop debris from washing over the motorway at spring tides.
152,000 tonnes of material including quarry stone has been loaded on to a reclamation on the seaward side of the causeway to compact the ground before new eastbound traffic lanes can be laid late this year. Traffic will then be moved on to the new structure, to allow existing lanes to be raised for westbound traffic.
New westbound on-ramp from Great North Rd has been completed.
5. Te Atatu interchange
Photo / Richard Robinson
Cost $50m
Completion 2017
Interchange bridge over the motorway and its five traffic ramps to be widened.
Also includes widening the motorway back to the Whau River.
Site clearance work started in February ready for main construction to start before winter.
6. St Lukes Rd to Great North Rd
Length 2km
Cost $70m
Completion Late 2016
Work due to start next month.
Includes widening the motorway to four lanes each way and broadening the St Lukes Rd interchange bridge to Western Springs to three lanes each way, plus a shared cycle-walkway.
7. Lincoln Rd interchange
Photo / Richard Robinson
Cost $135m
Completion June 2015
Work began in late 2010 and is about 75 per cent complete.
New seven-lane Selwood Rd bridge has been built over the motorway to replace the old two-lane structure.
Motorway approaches to the interchange are being widened from two to three lanes in each direction.
The interchange's four traffic ramps are being realigned and rebuilt.
Intersections are being signalised for safer pedestrian crossings.
Watch: Timelapse - Waterview Connection progress
Read more on the Waterview Connection plans on the NZTA website.
