Taking down Christchurch’s tallest building will be one of the biggest demolition jobs ever carried out in New Zealand and the most complex of all earthquake-related demolition in the city.
While it will be a loss to the city’s skyline, removal of the Grand Chancellor Hotel will enable hundreds of business owners to return to their premises and start their own rebuilding work.
Following a competitive bidding process, Fletcher Construction was awarded the contract for demolition in May 2011. Fletcher will manage the job, with most of the physical work being done by specialist Auckland demolition contractor Ward Group. Enabling works began in July and the first deconstruction action in late August.
Complex and delicate operation
When the contract was awarded, the structural stability of the building was still largely unknown. A full engineering analysis of the building was necessary before any work could begin. This enabled engineers to create an appropriate demolition methodology, taking into account how the building might behave structurally when forces are applied to it.
The result of analysis was selection of a careful ‘pulling apart’ process, where small segments of the structure are knocked out piece by piece and carried to ground. A large crane will pull apart the top 12 floors of the 26-storey building – a process expected to take 6 months. When completed, the bottom 14 floors will be pulled down in the same manner using a large excavator – this should take about 4 months.
The delicate approach is essential for both safety and protecting surrounding properties. The exact strength of the damaged building at each step of demolition cannot be known, and there is always the risk of some degree of collapse. Over 100 business premises are in the hotel’s ‘drop zone’, where they could potentially be hit by falling debris or worse.
Floor by floor, the building will have been reduced to a safe level after about 5 months. Adjacent business owners will then be allowed to return to their properties and resume operations. Central City Business Association Manager Paul Lonsdale is looking forward to ‘…getting more businesses up and operating out of good building stock’.
Total demolition by May 2012
The aftershocks of 13 June pushed work back by 3 weeks, with re-assessments of structural condition being necessary. The snowfall in the middle of August also caused delays to the first phase of demolition at the adjacent car park building.
Despite delays, the target for total demolition of the hotel remains May 2012. This date represents a landmark in Christchurch’s recovery. The city’s tallest and most dangerous building will be gone, and the way will be cleared for a significant section of the CBD to be revitalised.
Articles are correct at the time of publication but may have since become outdated.