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MARCH-APRIL 2014
EXPLOSIVE
DEMOLITION
was prepared that was verified using ASI
engineering simulation with the results
agreeing with the required performance.
To perform the detonation, the delays
between the column blasts were 300
milliseconds. The buildings’ central columns
were the first to be detonated and the
columns on the perimeter were the last.
Some of the columns on the perimeter
were not detonated to ensure that all debris
remained within the footprint of the
building itself. The charge ratio of the
implosion was 0.300 kg (0.66 lb) of explosive
for each cubic meter of column volume.
This ratio prevented any fragments from
penetrating the screens and hitting other
buildings in the vicinity. A total of 130 kg
(286 lb) of explosives was used, spread over
1,200 manually drilled holes.
PROTECTING THE PUBLIC
A 200 m (656 ft) exclusion zones was
established by the City Civil Defence
around the site, but as this team had never
experienced an implosion, it was necessary to
hold 15 meetings with all those involved. The
exact location of each employee was mapped
and the deadline for the evacuation of nearby
residents was set at two hours before the
demolition instead of just one hour. This was
to ensure the demolition happened on time
because the evacuation route is heavily used
on weekends by local beach-goers.
The implosion occurred without incident
at 8:00 am, exactly on time. No power cables
were damaged, no cracks in any of the
adjacent buildings were observed and all
the debris was contained inside the building
footprint, as predicted. The peak particle
velocity recorded by seismographs was below
3 mm/s, which was safely below the maximum
limit of 15 mm/s allowed for by Brazilian
standards.
■
under the guidance of a horticultural expert
who supervised the whole process. The
canvas and some flowers were placed at least
3 m (9.9 ft) away from the wall of the
buildings so they would not be affected by
any flying debris from the implosion.
Steel cables were connected to the second
building to guarantee that the fall of the water
tank did not happen in the direction of the
flower shop.
To prevent the debris from spreading in
the direction of Marques do Paraná Avenue
as well to the two sides, a careful blast design
The site cleared of a the demolition debris
The former Santa Monica buildings
were located on a slope in a tight site
