Contractors World UK & Ireland Vol 3 No 6 - page 23

• Undertaking extensive decontamination
of the internals of the tower and
conducting a video inspection to validate
the structure’s cleanliness
• Managing the demolition contractor
selection process and carrying out
rigorous examinations of company
structures, experience and safe working
practices, to ensure required standards
would be met.
Despite concluding that the level of risk
posed was minimised, manageable and
acceptable, RVA still incorporated into the
dismantling contract the requirement for the
appointed contractor to engage an addi-
tional specialist explosives consultant to
provide a secondary assessment and confir-
mation of their findings.
A test blast operation was completed two
weeks prior to the blowdown to validate
the design of the charge weight, drilling
pattern and primary protection.
Having removed one of the legs during
the test blast, the contractor devised a
collapse mechanism – involving the removal
by explosives of the remaining legs – to
ensure the tower would rotate and fall in a
north easterly direction.
The explosively charged legs were
wrapped with several layers of chainlink
mesh covered with geotextile fabric and
additional specially fabricated restrained
steel plating, to contain and minimise debris
spread.
A personnel exclusion zone ranging from
200 to 300 metres radius was established
immediately prior to the blowdown.
After six months’ of blowdown prepa-
ration in which RVA liaised with vibration
specialists, the National Grid – who had
major live assets adjacent to the site – and
local residents - the tower was reduced to
rubble in less than 10 seconds, using 13 kg
of explosives in 42 charge locations.
Page 23
Contractors World - UK & Ireland Vol 3 No 6
Kilometers of cables, ducting and pipework
had to be carefully removed and recycled
1...,13,14,15,16,17,18,19,20,21,22 24,25,26,27,28,29,30,31,32,33,...52
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