Tunnel work at Britomart and lower Queen Street is rapidly taking shape as part of the C1 contract.
A breakthrough to the Britomart station has cleared the way for the start of construction of the first of the two tunnel boxes under the Chief Post Office building.
Some of the in-ground piles installed at the time the Britomart station was built have been demolished following trench excavation by CRL contractors, Downer NZ Soletanche Bachy Joint Venture.
CRL Head of Delivery, Scott Elwarth, says that the ground support and groundwater cut-off completion enables us to excavate the trench.
“We have reached the stage of construction now where waterproofing membrane is being installed, clearing the way for the first CRL tunnel concrete pour inside the former Chief Post Office.”
The first tunnel box will be in the northern tunnel, which will be the CRL line coming down from Mt Eden to Britomart.
About two or three metres of spoil still needs to be removed from the southern tunnel within the post office and from the lower Queen Street area.
Mid-February, there will be a significant breakthrough of the wall separating lower Queen Street and the CRL tunnels across the Commercial Bay site, at which point a physical connection will be established from Britomart station, all the way up Albert St to Wyndham Street.
It’s going to be a big year!
2019 includes many other important developments in CRLL’s programme of works such as:
Successful completion of a project-related Strand rail upgrade in Parnell
Preparation work for the Aotea station getting underway - removal of canopies
Property acquisitions continue. This includes the purchase of sub-surface or underground land, and negotiations with property owners, particularly in Albert and Vincent Streets, impacted by alternations to the project’s designation
The project team is starting the meticulous process of evaluating two bids from New Zealand and international companies to design and construct the 3.45km-long underground project – a contract known as C3. CRLL CEO Dr Sean Sweeney says: “When we know who the successful bidder is, we’ll also know what the project, including the two underground stations, will look like and how they will be constructed, and how much the project will cost. At the end of the year we expect the successful bidder to start the main construction works.”
Below Albert Street, backfilling the space above the tunnel box continues and providing a strong base for the road itself. Fifty thousand cubic metres of aggregate is being used for the job – enough to fill 20 Olympic-sized swimming pools. While that’s a truckload of aggregate, it falls short of the 78 thousand cubic metres of dirt that was excavated under Albert Street in the first place to make room for the concrete tunnel box that will house the two rail tracks.
In parallel with backfilling, work is continues to complete the final section of the Albert St tunnel boxes.
From March, traffic northbound along Albert Street will be moved closer to the centre on to the existing construction traffic deck. This will allow our C2 contractor, Connectus JV, to remove pile capping beams, complete backfilling and reinstate the road with tree pits, stormwater catch pits as well as the road and footpath pavements.