42
DEMOLITION AWARDS SUPPLEMENT 2014
d
&
ri
URBAN/CONFINED
SPACEAWARD
Genesis Engineering II
Dadar residential tower,
Mumbai City, India
Genesis has gained its second shortlisted entry for
the contract for the demolition of the top 6.5 storeys
of a newly built 22 storey car park and residential
block of flats inMumbai City, India, to allow the
client, M/s Kohinoor CTNL Infrastructure Co Pvt to
reconfigure the internal layout to provide 8 flats per
floor instead of the four flats initially intended.
After examining a number of options, including
the use of compact excavators lifted to the top of the
building by tower cranes that thenworked their way
down using a combination of crushers and concrete
sawing. Genesis finally determined to demolish the
complete project by concrete cutting and dismantling
with the help of two tower cranes that were available
on the site.
At this height withwind pressure (around average
55 km/hr) and a southwest windwith themonsoon
season approaching it was a challenging project.
Genesis had tomanage the cement slurry created
during cutting operations so that it did not fall or be
carried by the wind onto neighbouring properties.
The size of the concrete slabs cut from the
structure could be no larger than 2 x 2.5m (6.6 x
8.2 ft) and a volume of 1,750m
3
(61,800 ft
3
) had
to be dismantled at an average of at least 11m
3
(390 ft
3
) per day.
Safety while dismantlingwas amajor concern.
All wire ropes, chain blocks, tower cranes, ropes and
every structural elements were tested as per the EHS
safety standards and norms. Safety railings were
installed at every locationwhere there were open
drops or open slabs. All necessary health and safety
inductions and trainingwas carried out on regularly
basis.
Wall saws andwire sawsmachines were used to
cut beams and columns, and electric floor saws and
automatic floor saws were used to cut the slabs. After
the pieces were dismantled on the top floor levels,
they were lifted down to the ground level and teams
of workers released the pieces lowered by the crane
and stack them for of-site disposal following initial
processing by 20 tonne excavators. Steel scrapwas
segregated and stockpiled for disposal.
CostelloDismantlingCo. Inc
Martin Luther King, Jr. School,
CambridgeMA, USA
Costello has been shortlisted for the work it
carried out on theMartin Luther King, Jr. School
in Cambridge, Massachusetts, which had reached
the end of its life cycle. Located in a congested
residential neighbourhood, the cost tomaintain
and update the old school did not match the energy
efficiency and quality of life increases that a new
school could offer.
After a substantial planning phase, complete
with substantial environmental testing, the city of
Cambridge released a demolition specification and
Costello Dismantlingwas selected as the demolition
contractor working under general contractor WT Rich.
Abatement work started in 2013with demolition and
site work finishing in 2014.
The environmental scope included removal of
friable and nonfriable asbestos from the interior of
the building, asbestos containingmastic from the
exterior, asbestos roofing, as well as PCB containing
caulking, mastics, paint and soils throughout the
building and site.
During the early phases of abatement work,
however, the City’s environmental consultant
discovered that the interior CMUwalls and the
exposed cast-place concrete structure were also
coatedwith PCB-containing paint and a radical
change to the scope of work had to be addressed.
After looking at several scenarios involving a sliding
scale of on-site abatement vs. bulk disposal, the
City of Cambridge and Costello decided tomaximise
concrete recycling – andminimise disposal – by
removing all the PCB paint from the structure.
First, approximately 1,725 tonnes of non-
structural CMUwalls were selectively removed and
disposed of as a PCB Bulk Product. Next, the entire
cast-in-place concrete structure was sandblasted
to remove all the interior paint and 0.06mm
(1/16 inch) of the concrete substrate. Extensive
testingwas then performed to demonstrate that the
PCB contamination had been remediated and the
remaining structure could be dismantled.
A Volvo 460 high reachwas the primary
demolition tool with several 460 and 480 Volvos in
a support role.
In total, Costello achieved a 99% overall
recycling rate, with 663.2 tonnes of steel, 15,000
tonnes of concrete and 522 tonnes of other waste
processed, with only 142 tonnes being disposed of
in landfill.
Genesis Engineering
LanghamPalaceHotel, India
Genesis Engineering has been shortlisted for the
demolitionwork undertaken on the Langham Palace
Hotel tower, built just two years ago as a 5 Star hotel,
but whichwas deemed not to be economically viable,
andwas therefore scheduled for demolition. Genesis
was taskedwith its removal, retaining the basement
retainingwalls and raft.
As a new structure, the tower featured good
strengthM50 grade concrete andwas the tallest
building in the area. Construction-wise it had a variety
of different floor levels and different space indexes,
two atriums were providedwithin the building and
there weremultiple height differences between the
floors. Being a 5 star hotel structure a number of
intricate space configurations had been created.
Before demolition Genesis planned the complete
mobilisation of machines on the structure and pattern
of each and everymovement and demolitionmethod.
Load carrying structures, complex locations, double
and triple height locations were identified alongwith
the beam and column supporting pattern, keeping in
mind the basement triple height wall and raft had to
be retained.
To ensure smooth execution and site operations
the two atriums were used for two different activities
- the front for steel disposal and the rear for debris/
waste disposal.
Four 7-8 tonne excavators were placed on top
of the structure by crane alongwith a 2.3 tonne
excavator, with the latter usedwhere load limits
prevented the use of the larger. A skid steer loader
removed debris to a debris chute area. Back propping
was done for the two floors below to provide support
and strength.
A proper debris chute wasmade to ground level,
fromwhere backhoes were used to remove debris,
where 20 tonne excavators segregated the debris and
steel if any. The client had a requirement of 3,000m
3
(106,000 ft
3
) of crushed debris at another project,
which Genesis delivered for recycling.
Once the building reached the 24m level,
20-24 tonnemachines were lifted onto the structure
to the service floor at 14m to carry out the further
demolition.
Once the demolition reached a suitable height,
ramps were then constructed to allow thesemachines
to track off the building and complete the demolition
to ground.
Steel was cut by gas cutting torches and shifted
manually in the front side atriumwhichwas our steel
chute. All the steel scrap generated from the structure
was sorted by the team at ground level.
WORLD
DEMOLITION
AWARDS2O14
URBAN/CONFINED SPACEAWARD
