2018 was a great year of progress for the City Rail Link (CRL). Well done team!
Here are some of the milestones.
Downer Soletanche JV workers began the final concrete pour for the 64th and final diaphragm wall (D-wall) in the former Chief Post Office (CPO) downtown. 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 also meant the end of the work there for the big piling rig Sandrine.
The bright red 90 tonne piling rig named Sandrine worked inside and outside the historic Chief Post Office building.
The rig played a major part in preparing for the tunnel construction in the building. The rig first began work around the outside of the building in Lower Queen Street and then in September 2017 was brought into the actual building.
Sandrine was returned to France at the end of January.
In Albert Street, construction of the first tunnel box started. It took three days to install the first 12 metres of the waterproofing.
The work involved installing steel mesh and pin into the wall of the trench for temporary rock support. This was followed by ‘shotcreting’: this means spray-concreting a smooth surface for the waterproofing membrane of the tunnel box. 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.
There are 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 was constructed, the team could start backfilling. These steps were to be followed, stage after stage, for approximately 350 metres of tunnel.
Meanwhile, bulk excavation of the cut-and-cover trench on Albert Street was continuing towards the Customs Street intersection.
The construction of the Albert St tunnel box was going so well, the first concrete pour took place.
Once the first 12 metres of waterproofing was completed for the first slab, reinforcing works started.
Two tonnes bundles were individually lifted between the struts to the trench floor by contractor CRS Ltd. It took eight steel fixers five days to tie together one floor slab (12 metres). Twenty tonnes of steel were used for the first slab.
City Rail Link construction work was getting underway in Mount Eden for the first time.
Contractors will be diverting a section of the existing Mt Eden stormwater pipe and creating a new alignment between Water and Nikau Streets to help CRL create a redeveloped Mt Eden train station.
The existing stormwater pipe is in the path of the new CRL tunnels that will be built at Mt Eden. The project has already bought more than two hectares of land around the station.
All the surface work for the stormwater diversion will be on CRL-owned property with minimal effect on traffic.
The tunneling will be done by a German-built Herrenknecht AVN machine named Jeffie. The name was chosen after a CRL Facebook poll.
The most popular name in the poll was Jeff but traditionally such machines adopt a female name so Jeffie, a popular girls name in the early 1900s, was chosen. Naming digging equipment after women is said to be a tradition that dates to the 1500s when miners prayed to to St. Barbara to keep them safe underground. Saint Barbara is the patron saint of armourers, artillerymen, military engineers, miners and others who work with explosives because her legend associated her with lightning.
We were a step closer to be able to start tunnel excavations in the former Chief Post Office (CPO) building.
The first area of the CPO building was load transferred onto one of the structural steel underpinning frames. There are 12 frames.
Why this is significant is because once all the load transfers are completed, they could then start tunnel excavations safely.
Also this month another milestone near there- the completion of secant piling which has been happening in Lower Queen Street outside the CPO. The secant pile walls will connect the excavation under Britomart to the excavation at Precinct Properties’ Commercial Bay development on the other side of Lower Queen St, where CRL tunnel boxes are being constructed.
70 secant piles had to be installed. Secant piling is construction of intersecting reinforced concrete piles. These piles lock together for strength and control any groundwater ingress into the tunnel excavation.
In the Albert Street tunnel trench (right), the Connectus construction team (McConnell Dowell and Downer) had poured the 5th wall.
This meant that 60 metres of the tunnel walls were complete.
Another Connectus crew was preparing for the first sections of the roof and tunnel.
Outside the Chief Post Office, excavations on Lower Queen Street were underway for construction of a pile cap on the new secant piles. Inside, excavations of the temporary former Chief Post Office floor were underway.
Tunnel excavation under the Customs Street intersection started.
That work paved the way for construction of the City Rail Link (CRL) tunnel box section to link the Albert Street trench with the tunnels being built under the Commercial Bay development.
Contractors Connectus also started pouring the concrete that will form the Albert Street twin tunnel roof.
City Rail Link (CRL) sponsors – New Zealand Government and the Auckland Council – agreed to increase their investment in the project to cater for larger-than-expected growth in rail patronage across Auckland.
The new agreement means the tendering process for the project’s main stations and tunnels contract can now incorporate longer platform tunnels at Karangahape Station to cater for nine-car trains (instead of six), a second Karangahape Station entrance at Beresford Square and additional station work at Britomart, Aotea and Mt Eden stations.
A start was being made on excavating the 14-metre-deep trench that will contain CRL’s twin rail tunnels under Britomart Station and Lower Queen Street.
The excavation follows two years of careful preparation work to protect Britomart Station’s historic Chief Post Office (CPO) building and support the ground before the trenching and tunnel construction begin.
Contractor Downer-Soletanche Bachy Joint Venture (DSBJV) started by removing a five-metre layer of ground from Lower Queen Street. This lowered the ground level sufficiently to allow excavators to start digging under the CPO building.
A single 25-metre wide trench was being excavated in Lower Queen Street and two 10-metre-wide trenches under the CPO (the two future CRL platforms located on the far sides of the station).
The Request For Proposal (RFP) was issued to the two shortlisted tenderers for the major contract for the stations and tunnels (we refer to this as contract 3).
The RFP process will be completed by next February and the contract should be awarded by the end of March 2019.
CRL released new video fly-throughs of the CRL stations.
The Minister of Transport Hon. Phil Twyford, Mayor of Auckland Phil Goff, Finance Minister Hon. Grant Robertson and Deputy Auckland Mayor Bill Cashmore (left to right in photo) visited the CRL Albert Street trench.
KiwiRail work was starting on improvements at the Strand. The rail works planned include introducing a new track cross-over point that allows trains to more easily access the existing Strand station and stabling facility, along with some track realignment and modifications to overhead line and signalling equipment. Once the CRL is operational, The Strand works will mean there can be an increased frequency of trains on the Auckland rail network.
The re-instatement of Albert Street got one step closer. The project started the backfilling of the trench which runs directly underneath Auckland’s busy Albert Street.
City Rail Link CEO, Sean Sweeney, said that the milestone marked the start of the last stage of the Albert Street works needed before the road can be re-instated and returned to road users and pedestrians – expected late 2020.
Backfilling of the trench will take until mid-2019 to complete and a total of 50,000m3 of materials will be used to fill it. That’s the equivalent of 20 Olympic-size swimming pools.
The material will be a mixture of crushed concrete, crushed rock, sand and flowable fill.
In Lower Queen Street, the load transfer of the former Chief Post Office (Britomart) building was now complete.
DBSJV had been completing the weight transfer of the 106-year-old Category 1-listed heritage building onto a series of underpinning frames.
This will protect it from damage while CRL infrastructure is built underneath.
We achieved one of the most complex engineering challenges for the City Rail Link (CRL) to date - one which took two years of planning and preparation by NZ and international experts.
In order to construct new railway tunnels under the Britomart train station, the building, the former Chief Post Office which opened in 1912, had to first be moved onto temporary foundations to keep it protected during construction.
Elsewhere, CRL’s Albert Street tunnel box construction was now about 63 per cent complete, with 264 metres of floor, 240 metres of wall and 156 metres of roof poured at the southern end of the trench.
Contractor Connectus Joint Venture continued the backfilling of the trench the tunnel box sits in.
To date, more than 4,000m3 of material had been placed on top of the tunnel box, about 10 per cent of the total amount required. This enabled more than 180 metres of temporary steelwork to be removed.
Sustainability is a big focus for CRL and it was recognised this month. The project won both the Efficiency Champion category and the Supreme Award - the NZI Transforming New Zealand Award - at this year’s NZI Sustainable Business Network Awards.
A ceremony was held to mark the breakthrough from the Albert Street tunnels to CRL tunnels across the Commercial Bay site.
The breakthrough was a gradual process over the previous month, requiring a staged approach to excavation, construction of shotcrete support between piles, and demolition of temporary concrete piles separating the two sites.
The tunnels between the two sites, meet under the Customs Street traffic deck which was built last year to keep traffic moving while the work is carried out underneath.
This means the CRLL contractor Connectus the McConnell Dowell and Downer Joint Venture team can complete the construction of the remaining third of the tunnel box and backfilling of the trench will continue until it is completely covered – expected to be mid-2019.
Early 2019, the tunnels from the former CPO (Britomart) site will also connect to tunnels across the Commercial Bay site – providing a complete tunnel section from Britomart through to Wyndham St.
A snapshot of the Albert Street Trench in numbers:
846,000 hours worked to date
360 piles installed
155 steel struts
250 services relocated
50,000m3 of backfill to complete the trench
10,000m3 of tunnel box concrete
Also in December, a blessing was held for Jeffie, the tunnel boring machine being used at Mt Eden.