33
d
&
ri
DEMOLITION AWARDS SUPPLEMENT 2014
CONTRACTOF THEYEAR
OVERUS$1.5MILLION
continued
Keltbray
BlockW5,
London, UK
Keltbray has been shortlisted for the contract it
completed at BlockW5 in London due to the
complexity of the highly sensitive and confined
environment and the technical innovation of the
demolition process that was undertaken.
The project scope of works for the demolition
contract included the following key elements: design,
fabrication and installation of temporary works to
retained façades; asbestos removal; soft strip; stone
dismantling and salvage for re-use; lead dismantling
& salvage; scaffolding: underpinning; mini piling;
groundworks enabling; structural demolition
The site covered buildings formerly known as 169
NIKAUContractors Ltd
HeritageHotel Tower,
Christchurch, New Zealand
The Heritage Hotel Tower was a 13 storey hotel tower
block located in Cathedral Square in the Christchurch
CBD. Adjacent to this is the Old Government Building
(OGB), a heritage building that was not affected
structurally by the Canterbury earthquakes and had
to bemaintained and occupied as a hotel during the
demolition.
After countless efforts to save the tower, it was
decided it was not economically viable to do so,
therefore the owners of the tower ordered demolition.
Nikauwon the contract to demolish the tower, but
insteadmoved for a deconstruction rather than a
demolition due to the fact the OGBwas only 6m
(20 ft) to the north side, theMillenniumHotel was
directly adjacent with 150mm (6 inches) between
them, the Heritage car park again 150mm away
and the only access was to the south following the
gaining of the contract to demolish the building for
the use of the land as a staging area.
After removing the soft furnishings Nikau
mobilised a 200 tonne crawler crane for lifting 20
tonne sections by twomethods, concrete cutting
for the exterior concrete elements and using small
machinery to rock break internal columns and
beams. For protection to adjacent property Nikau
used a combination of scaffold and developed a
rock net screen hanging from a 55 tonne crane at
full height so that the workers couldmove the net
into strategic locations around the building. Nikau
deconstructed the building to level 2 thenmoved
heavymachinery in to complete the remainder of the
demolition.
To add to the complexity of the project, three live
transformers that provided power to the city needed to
remain undamaged during the deconstructionworks.
The locations of these transformers were directly on
the north, south, and east side of the deconstruction
works. Nikau successfully completed the project on
time and on budget incident free.
WaltersGroup
CwmbranCountyHall and
CivicOffices,Wales
When a structural survey revealed that Cwmbran
County Hall and Civic Offices had “concrete cancer”
with an estimated repair bill of in excess of £30
milion (US$49million), Monmouthshire and Torfaen
Council acted to condemn the building complex
and earmark the site for future redevelopment. As
well as the challenge of demolishing the various
heavily reinforcedmulti-storey buildings and high
rise chimney structures on the site, the works also
providedWalters with other hurdles to overcome.
Opposition to the scheme among local residents was
intense, leading the company to hold a ‘Residents’
Meeting’ to allay these, which proved successful.
Breaking out 30,000m
3
(1.06million ft
3
) of
heavily reinforced concrete adjacent to residential
areas had high potential to be amajor nuisance
issue soWalters instituted a number of intensive dust
suppression efforts, as well engaged an independent
noise consultant who produced a noisemap for
the residents that was updated regularly by frequent
noisemonitoring on site. Walters also had to content
with the fact that the site was identified as a Site of
Importance for Nature Conservation, resulting in an
external soft strip being carried out in conjunction
with the internal. Walters provided a purpose built
‘bat house’ where bats discovered in the structures
during this could be relocated.
Following the removal of notifiable and non-
notifiable asbestosmaterials, Walters undertook
an stripout of the 40,000m
2
(430,500 ft
2
) of
floor area. Removed soft materials were deposited
to ground level via externally constructed scaffold
chutes. Walters commenced structural mechanical
demolition of the various heavily reinforcedmulti
storey and high rise structures comprising the County
Hall and Civic Office site in earlyMarch 2013. By the
end of May, just over 12weeks later and ahead of
programme, all superstructures on the site had been
safely reduced to ground level.
to 189 Regent Street, No 1, 2, 3& 4New Burlington
Street (NBS) and No 2, 3& 4New Burlington
Place (NBP). The 10 existing buildings on site
were generally constructed in the early 1900s and
had been extensively altered during the subsequent
80-100 years. A single basement level extended over
the entire site.
The project scheme required the Regent Street and
NBS façades below the cornice levels to be retained,
while No 1 and 2were to be retained in their entirety
due to their Grade II listing.
The demolitionwas carried out safely without any
incidents and to budget, and despite serious delays
caused by the neighbouringW4 construction site
the demolition phase finished twoweeks ahead of
schedule.
WORLD
DEMOLITION
AWARDS2O14
