New delay for project
Metro sports facility land sinking
Land sinking by about a metre has delayed construction of Christchurch’s troubled metro sports facility by about five months.
A 10m2 area on the southern edge of the $317 million project site has sunk by an average of 90cm after a dewatering well malfunctioned and sucked out soil and sand from underground.
The sinking ground is being strengthened by injecting 80 concrete columns up to 15m into the soil. The work began in December and will not be completed until around April.
The Christchurch rebuild anchor project has been beset with delays and cost rises. It was initially set to be completed in late 2021 and to cost $301m but is now not expected to be finished until spring 2024 and to open in early 2025, at a cost of at least $317m.
A spokesperson for Crown rebuild company Ō tā karo Ltd said the ground-strengthening work had delayed completion of key parts of the building, which is officially named Parakiore Recreation and Sport Centre.
‘‘The remediation work has delayed the construction of a switchboard room in that area that houses the main power connection for the facility and a communications room for the building’s IT equipment,’’ he said.
‘‘The delay to the project is equal to the amount of time it takes to remediate the subsidence.’’
The spokesperson said people were confusing the sinking ground with the planned settling of the building during construction.
‘‘There has been minor settlement across the buildings. The settlement has ranged from approximately 0.5cm to 6cm, with the potential for a few more millimetres of settlement when the pools are filled, given the extra weight this will add.’’
He said the settlement was within expected limits.
‘‘All large buildings like Parakiore settle as more weight gets added to the foundation during the construction process.
‘‘Tolerances are built into the design to cater for this. We appreciate there appears to be some ongoing confusion in the public domain between this and work to strengthen a small area of softer soil to the south of the aquatics building, otherwise known as subsidence.’’
The lead contractor, Australian company CPB Contractors, was responsible for the remediation work and the cost of the delay, the spokesperson said.
CPB Contractors is seeking an extra $212m to deliver the project but the Government has disputed the claim and has insisted it won’t delay the opening any further.
The contractor is in dispute with Ō tākaro over six claims for extra money.
CPB Contractors did not respond to a request for comment.
The concrete column technique, known as jet grouting, was
used during repairs of the Christchurch Town Hall and the Christchurch Art Gallery after the 2011 Canterbury earthquakes.
The Ō tā karo spokesperson said the metro sport building had been designed for the site, between Moorhouse Ave and St Asaph St, which is known to have a high water table. ‘‘So the majority of the pools did not have to be installed into this ground, the site was raised up to 2 metres in places. This is why Parakiore sits much higher than the neighbouring streets. However, the construction of the 5m-deep dive well and basements did require construction work to be carried out in the water table.
‘‘To allow this work to take place, groundwater was temporarily pumped out and away from the area. Unfortunately, along with the water, one of the wells at the southern end of the aquatics building also appears to have malfunctioned and to have drawn out soils and sand, which has resulted in the softening of the soil. This posed a risk that it would behave differently in an earthquake in the future by being more susceptible to liquefaction.’’
The facility will have a 10-lane, 50m pool with 1000 seats for spectators, a diving pool, five hydroslides and several indoor courts for various sports. Work started in August 2018.