28
MARCH-APRIL 2014
d
&
ri
EXPLOSIVE
DEMOLITION
minimise ground vibration to a maximum
recorded level of just 7 mm/s peak particle
velocity measured at 14 m (46 ft) from the
elevation of the structure. This level was well
within the 50 mm/s limit specified in the
British Standard BS7385 for Measurement of
Groundborne Vibration and the US Bureau of
Mines (USBM) Air overpressure levels were
recorded as being less than 124dB.
COMMUNITY LIAISON
Before the demolition could take place
Safedem’s dedicated community liaison team
had to evacuate over 600 residents from the
145 m (475 ft) exclusion zone. Throughout
the project the team consulted with residents,
commercial properties, schools and churches.
To manage the process, the evacuation
was divided into zones of approximately
200 households – each with a dedicated
evacuation team leader. Over 40 Safedem
staff carried out the evacuation – making
initial contact with residents, coordinating
transportation to rest centres and working
closely with staff and residents of a large
sheltered housing complex.
The Safedem team applied established
technology in an innovative
way to expedite the evacuation
process. Throughout the week
before the blowdown, each
resident was issued with a pass
with a bar code. When leaving
the zone via the dedicated gates,
the barcodes were scanned and
the resident’s information was
logged as having duly vacated
the zone. This information was
After the blast
power wash crews to clear roads, footpaths
and structures of dust.
The blowdown was carried out overnight
in arctic conditions. The security staff and
police were exceptional and were described
by William as being ‘the true heroes of
the operation’. Dust suppression water
cannons froze but all the staff maintained a
tremendous spirit throughout the difficult
conditions.
Safedem delivered the project on time
(and within Network Rail’s tight timeslot) and
under budget. The blast design, and Safedem’s
assurances that debris would be
contained without rolling down
the rock face, allowed the client
to save a potential expenditure
of a £450,000 (US$740,000)
provisional sum that had
been allowed for rock face
stabilisation and netting works.
Regeneration manager
Russell Smith of client River
City Homes said of the project:
“ This complex project has been
well delivered and RCH has
been delighted with Safedem’s
attention to detail throughout
every step of the project. The breadth of
knowledge and experience brought to the
project by Safedem at every level within
their organisation, from the CEO to the
site labour, excelled at every level turn.
Teamwork, effective communications and
close coordination of all parties meant that
site operations were carried out safely and
ultimately the demolition programme was a
great success.”
■
electronically linked to the control room. This
process avoided any build-up of residents at
the exit gates and dramatically reduced the
time taken for gate staff to scan lists of names
and check off residents from a list of over 200.
The use of established technology in
an innovative way undoubtedly helped the
evacuation process, which despite the large
numbers involved, was completed 45 minutes
ahead of schedule.
Following the demolition, the team
supervised the immediate clean-up process
with the deployment of road sweepers and
