Revised Summary of “4 Ways to Demolish a Building” and Reader Response draft 3

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 crusher 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, this is to prevent soil erosion. Clean concrete from demolition debris can recycled to build footpaths and roadside drains. Remote-controlled machines reduce the risks for the operator compared to conventional machines, as the operator can 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, as this method produce lesser harmful substances compared with other demolition methods. Wong (2018) stated that use of small machines for top-down method reduced the noise level emission, therefor this method is suitable for urban areas. 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.". This statement indicted that 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 protection measures allow the top-down demolition to emit less hazardous substances. The implosion, high reach arm, wrecking ball and selective demolition methods are not suitable for current demolition practices with the disadvantages mentioned.  

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