In the article “4 Ways to Demolish a
Building”, Rodriguez (2018) stated that ways of demolishing a building depend on the
land area, building materials, purpose of demolition and disposal of debris. The
author also mentions the four methods of building demolition. The author implied that the implosion method is suitable for large scale
buildings. Detailed studies of the buildings’ structural drawings are necessary
to identify the main beams and placement of explosives. The author stated that
high reach arm method, which involves the removal of inter-connected beams is suitable for buildings above 20 meters and it is a safer
alternative compared to the wrecking ball demolition. Experts are required to operate the wrecking ball during demolition due to
space constraint and equipment load. The author mentioned that this method
emits dust, vibration and noise. He stated that selective demolition is a cost-saving
method, suitable for reusing materials for future construction. High labor
requirements and time are needed for selection of reuse materials. Based on the
points elaborated, although the writer addressed the four ways to demolish a
building, he should have mentioned the top-down demolition method, as it is
the most commonly used demolition practice, its environmental advantages and the
dis-advantages of the four demolition methods mentioned by the writer.
Firstly, the top-down demolition method hoists the remote-controlled concrete breakers and
crushers machines to the rooftop and demolish the building from a top-down
manner, floor by floor. The
top-down demolition begins with floor slabs, then the beams, columns and ends
with the foundation. It introduces temporary supporting structures named
“propping” to ensure safety. Haziq (2017) stated that after demolition the
ground must be filled with soil to ensure grass grows. Clean concrete from
demolition debris are recycled to build footpaths and roadside drains. Remote-controlled
machines reduce the risks for the operator compared to conventional machines, as
the operator could control the machines from a distance.
Secondly, top-down
demolition method allows the building to be demolish via a clean and
environmentally friendly way. Ferro
(2013) stated that demolition method could be eco-friendly and Wong (2018) stated that used of small machines for top-down method reduced the noise level
emission. Noise barriers could be also erected around the site to comply with
the permissible noise levels. Dust emission
could be reduced by using a mist machine and dust screens. Top-down demolition can
reduce the percentage of harmful constituents released to the environment by
reducing the dust emission.
Lastly, top-down demolition is a
preferred demolition method compared to the other four demolitions. The
implosion, high reach arm and wrecking ball demolitions create lots of dust,
vibration and noise. Haziq (2017) stated that implosion and wrecking
balls demolition methods were not suitable for high and compact buildings. This
point can be further supported in the news release “Demolition in Singapore is
not what you think” (2018). Different types of demolished debris mixed and smashed in
to small pieces, renders it impossible to meet the local reuse and recycling of
materials regulations. Pittman (2004) mentions that Ms Morello, manager of Penhall company stated: “I haven't seen the 'headache ball' in a long time.".
Through this statement, the wrecking ball method decayed from the demolition
practice in a long time. Loon (2012) stated that the selective demolition is
labor intensive, which needs labor contractors to presort the demolished
materials for recycling.
In conclusion, the top-down
demolition is a safer demolition method as it involves remote-controlled machines and beam support structures, which reduces the
workplace accidents. The environment prevention measures allow the top-down
demolition emits less hazardous substances. The implosion, high reach arm,
wrecking ball and selective demolition methods are not suitable for current
demolition practices with its disadvantages mentioned above.
Reference
Demolition in Singapore is not what you think. (2018).
Jinbiao single-post.
Retrieved from
http://www.jinbiao.com.sg/single-post/2018/02/02/Demolition-in Singapore-is-not-what-you-think
Ferro, S. (2013). Japanese eco-friendly building
demolition method harvests
energy as
it destroys. Popular science.
Retrieved from https://www.popsci.com/technology/article/2013-01/demolition-goes-eco-friendly-japan
Haziq, M. (2017). No explosives or swinging balls:
How high-rise demolitions go
down in
Singapore. (2017). Channel NewsAsia.
Retrieved from https://www.channelnewsasia.com/news/singapore/no-explosives-or-swinging-balls-how-high-rise-demolitions-go-9425362
Loon, B. (2012). Conducting a selective demolition. The American Builders
Quarterly. Retrieved
from https://americanbuildersquarterly.com/2012/09/26/conducting-a-selective-demolition
Pittman, J. (2004) Wrecking ball gives way to new
method of structural
demolition.
Bizjournals.
Retrieved from
https://www.bizjournals.com/wichita/stories/2004/08/02/focus2
Rodriguez, J. (2018) 4 Ways to demolish a building. The balance small business.
Retrieved from
https://www.thebalancesmb.com/ways-to-demolish-buildings-844420
Wong, D. (2018) Rochor Centre to be torn down floor by
floor. The Straits Times.
Retrieved from https://www.straitstimes.com/singapore/housing/rochor-centre-to-be-torn-down-floor-by-floor
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