The CRL is the largest single transport infrastructure project in New Zealand's history.
It has been a vision for Auckland since the 1920s.
This was the official start
Read the CRL Business Case
This 2015 document was Auckland Transport’s internal business case to facilitate the Gateway Review process prior to letting contracts for enabling works construction. It was not a joint business case with government.
Here are the big milestones in 2018:
Albert Street Tunnel Box Pour
01 March 2018
The construction of the Albert St tunnel box is going well. The first 12 metres of waterproofing has been completed for the first slab so reinforcing works have just started.
The first slab will be completed on Saturday and the first pour will begin on Monday. Two tonnes bundles have been individually lifted between the struts to the trench floor by contractor CRS Ltd. It takes 8 steel fixers 5 days to tie together one floor slab (12 metres). 20 Tonnes of steel are used for the first slab.
Sandrine finishes her work
31 January 2018
Sandrine, the bright red 90-tonne piling rig has finished working around the historic CPO (Britomart) building for contractor Downer Soletanche-Bachy JV and was returned to France.
With Sandrine's help, 64 diaphragm walls (or D-walls) were built by the construction workers. The wall panels form the structural support for the tunnels to be built in the building and also prevent water ingress.
Albert Street Trench Construction Starts
14 February 2018
In Albert Street, construction of the first tunnel box is starting.
It takes three days to install the first 12 metres of the waterproofing.
The first step of the works is to place a first layer on the wall and floor.
This material is called filter cloth. It will protect the waterproofing membrane from perforation by the concrete.
Once installed, the waterproofing membrane can be placed on top.
Meanwhile, bulk excavation of the cut-and-cover trench on Albert Street is continuing towards the Customs Street intersection.
Behind the excavation stage, the construction of the tunnel box is getting underway.
This means installing steel mesh and pin into the wall of the trench for temporary rock support.
This is followed by ‘shotcreting’: this means spray-concreting a smooth surface for the waterproofing membrane of the tunnel box. The shotcreting team is currently completing the first 44 metres section of wall.
The last preparation step is the ‘blinding layer’: pouring concrete on the floor of the trench to form a flat, smooth layer for the concrete slab that holds the tunnel rails. The first 44 metres of blinding is already complete.
The team will then start the construction of 29 sections of tunnel box, each 12 metres long.
The waterproofing membrane is installed on the floor and walls, steel reinforcement is fixed for the base slab, and formwork installed before finally pouring tunnel concrete.
Once about 60 metres of the tunnel box is constructed, the team can start backfilling.
These steps will be followed, stage after stage, for approximately 350 metres of tunnel.
In the second half of the year, the Albert Street trench excavation will be completed and connected to the Precinct Properties site on the corner of Customs and Lower Albert Streets.
The tunnel box construction will continue all year, following behind the excavation.
By mid-year, the Albert Street trench will start to be backfilled between Wyndham and Swanson Streets and the first portion of road reinstatement is expected to start at that location before the end of the year.
Last concrete pour for CPO D-walls
31 January 2018
Downer Soletanche JV workers have begun the final concrete pour for the 64th and final diaphragm wall (D-wall) in the CPO. The walls were required to support the CRL tunnel excavation under Britomart Station.
The D-walls not only provide soil retention and control groundwater ingress but support the weight of the historic building during tunnel construction. It will also mean the end of the work there for the big piling rig Sandrine.
^ back to top