Country’s largest construction project update

Mary Searle Bell catches up with Auckland’s $4.45 billion City Rail Link post pandemic lockdown.

All six City Rail Link sites reopened at the end of April after work such as building consents, designs and planning was achieved by staff from their homes.

However, CRL chief executive Sean Sweeney says it will be some months before the project has a clearer view of the lockdown’s impact on costs and construction timetables.

“Key factors in our evaluation will be the health of our economy and the efforts internationally to control the pandemic as both affect access to workers, and the viability of those companies that supply us with our necessary materials and machinery.”

Last month Sweeney said more than 40 project workers remain overseas unable to get into the country.

“Because of our size we’re aware of the big role we have in quickly getting the economy moving again, supporting the contracting and infrastructure industries and seeing our workers safely back on the job,” he says.

Options to speed up work have been put in place including double shifts implemented since mid-May, and shifts extended for up to 16 hours a day at the Mt Eden and Karangahape sites.

The Link Alliance had to revise plans to cover night-time construction issues including traffic management, disruption, noise and vibration, with noisy works finishing before 7.00pm wherever possible. Mats to absorb noise are used and flashing beacon lights on machinery turned off to reduce light nuisance. Workers are instructed to leave sites quietly at night.

“We’re very mindful of our obligations under legally binding consent conditions and of the great support we get from our neighbours and the wider community,” says Sweeny.

“Our priority is to keep neighbours and community organisations well informed through a whole raft of different communication channels so they know what we are up to.”

City Rail Link has also approached the Government to have the project declared an essential service on economic grounds, which would enable overseas workers to return and, after a two-week quarantine period, resume work on the project.

Construction over rail inks

KiwiRail made the most of Queen’s Birthday weekend last month to install a new scissor crossing as an important step forward for the Mt Eden site works, where workers required over 80 hours of train-free track access.

Working around the clock, KiwiRail contractors removed a pinch point to provide more flexible track use. KiwiRail chief operating officer Todd Moyle says the scissor crossover will allow trains to switch tracks when travelling in either direction, which is critical as train frequency increases.

“The new track will ultimately provide CRL workers the space needed to do their job safely while commuter and freight trains continue to travel along the Western Line.”

To make things happen faster, the construction team built the crossing off site before a crane lifted it into position.

Sitting on six-metre-long concrete sleepers that span two tracks, the new track was installed in 11 different sections, with the heaviest being over 25 tonnes.

Dale Burtenshaw, deputy project director for the Link Alliance, says this work is crucial to CRL construction in Mt Eden.

“It means that a single line can run through Mt Eden while we undertake construction in the rail corridor for the new rail trenches and redeveloped station.”

While trains will continue to use the line through Mt Eden with little disruption to existing timetables, the station is to close in July for four years, which attracted criticism from the local community that had previously seen a temporary station set up in nearby Newmarket during a similar construction project. A free bus service has been in use for commuters who would normally use the closed station.

Burtenshaw says the decision to close Mt Eden Station for four years was not made lightly.

“Our priority is safety and if the station remained open there was risk to workers and the public walking through what will be a live and complex construction site.

“Building a temporary station was also investigated, but there was not enough room inside our construction zone.”

The Mt Eden works programme includes shifting underground utilities, laying four tracks instead of the present two, and building a trench for two of those tracks to connect with the tunnels.

Tackling the unexpected

Just a few metres below ground lies a web of many thousands of metres of pipes, tubes, wires and ducting that carry gas, water, electricity, the internet and sewage and waste throughout the city.

On a project like CRL, many of these need to be relocated before construction can proceed.

“Relocating utilities is our first cab off the rank if you like – our first big task before the heavy construction machinery can move in,” says Burtenshaw.

“It is technical and challenging work demanding a lot of planning and integration.

“At times we are working with utilities up to eight metres deep, and often with half a dozen different utilities services/providers, which all require coordination with each other.”

Relocating utilities at Aotea Station has uncovered some buried gems from Auckland’s past – a disused well, a boiler, and bricks from a demolished hall – but not all the surprises found below ground have been historical.

While most of the utilities’ web is well mapped and contractors know exactly where to dig, that is not always the case as Link Alliance site engineer Abhi Amin discovered.

“There was a map alright, but what it was telling us and what we actually discovered were two very different things,” he says.

The map featured a pipe of natural gas running at right angles from a main under Albert Street to the Crowne Plaza hotel and a neighbouring office block. However, instead of being buried below the service lane which runs beneath Albert Street, the pipe was located in the ceiling of the service lane.

“Exactly where we didn’t want it to be – right in the way of our planned piling for a diaphragm wall to support the new station,” says Abhi.

“Shifting it quickly became a critical part of the construction programme.”

Relocating the gas in a 70-metre-long trench underground was a complex operation.

“The job didn’t look hard on paper, but everything about it was complex.

“There were a lot of consents needed, a clear route had to be found around other services for the new pipe, and a lot of people needed to be kept informed – the hotel, the offices next door, and all the people who relied on the service lane for access and parking.”

With the gas line now safely relocated and clearly mapped, the way is now clear to start D-wall construction for Aotea.

Preparing the TBM

Following a nationwide poll, Dame Whina Cooper shares her name with CRL’s tunnel boring machine (TBM).

Tradition dictates that a TBM cannot start work until it has a woman’s name to honour St Barbara, the patron saint of underground workers, as a sign of good luck for the project ahead.

“We were looking for the name of a New Zealand woman who inspired – brave, compassionate and fearless – and all those outstanding leadership qualities are well and truly represented by the very remarkable Dame Whina Cooper,” says Sweeney.

German company Herrenknecht is building the $13.5 million TBM at its factory in China and it is due to arrive in kitset sections in October and will be assembled at the project site at Mt Eden.

It will then start the first of two 1.6-kilometre underground excavations from Mt Eden to Aotea Station in the central city to connect with the twin tunnels already built from Britomart Station and under Albert Street.


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