The 1972 Christchurch Town Hall of the Performing Arts in South Island, New Zealand is currently undergoing a major NEC-procured restoration following extensive earthquake damage suffered in 2011.
Much of the ground beneath the building’s 2500 seat auditorium, 1000 seat theatre, four conference rooms and restaurant liquefied during the deadly 6.3 magnitude earthquake, resulting in differential settlements occurring across the site of 300 to 600 mm.
In 2013 Christchurch City Council agreed to go ahead with repairing rather than demolishing the iconic grade 1 listed venue and embarked on a five-year, NZ$127.5 million (£72 million) conservation project.
NEC service contracts
The Council engaged the original architect Warren and Mahoney and consulting engineer Holmes (civil, structural, fire) along with commercial manager Rider Levett Bucknall, mechanical engineer Aurecon and electrical engineer Cosgroves under the NEC3 Professional Services Contract (PSC) option A (priced contract with activity schedule).
Enabling works contractor City Care was then engaged under the NEC3 Term Service Contract (TSC) to remove existing heritage fabric for later reinstallation and to prepare the Town Hall for the main contract. As part of the enabling works package, the Council worked with City Care under an early contractor involvement arrangement to develop an indicative construction programme as well as highlight any buildability issues.
NEC works contract
In June 2015, main contractor Hawkins Construction was employed under the NEC3 Engineering and Construction Contract (ECC) Option B (priced contract with bill of quantities). The repair strategy required the installation of 1100 jet grouted columns 6–8m long under the building, structural repairs, re-levelling of the upstairs function room, reinstatement of all removed heritage fabric, and installation of new mechanical and electrical equipment and infrastructure.
A total of 27,000 m3 of concrete has been placed under the ground floor to provide an earthquake-resistant wall of ‘soilcrete’ which will protect the building from future ground movements. The existing ground floor concrete slab was then replaced with a new slab with an average thickness of 900 mm across the whole building. Work is due for completion in mid-2018.
Christchurch City Council project director Patrick Cantillon says, ‘NEC was selected as the preferred form of contract as we required a higher-than-normal level of collaboration, not just from our main contractor but also from the design team and supply chain partners. There is no other contract suite in New Zealand that offers this level of collaboration – it is hard-wired into all NEC contracts.
‘We have managed to create an environment using the NEC philosophy that is designed to ensure the project will succeed, along with a ‘no surprises’ and strong safety culture. We are still tracking to budget and time for a mid-2018 completion.’