Pre-Planning

Demolition is the process of pulling down a structure either for the purposes of creating a new property or if the existing structure has reached the end of its lifespan (service life) or if the structural soundness and functional performance of the existing structure are in doubt (Thomsen, et al., 2011). In construction industry, demolition is a common activity before commencement of actual construction of the new structure as it gives way or space of the new structure to be constructed. This paper presents a demolition plan of a 1500m² site that has an existing vacant single storey factory to give way for construction of a two storey apartment block. The site is located in Chadstone, Melbourne. The demolition will involve bringing down the entire property and valuable materials will be preserved for reuse or recycling.

Before the structure is demolished, comprehensive planning has to be done. This is so as to ensure that the right resources are available for the actual demolition and that the process is done in an efficient, safe and cost-effective way (Rathi & Khandve, 2014). The main activities that will be undertaken during pre-planning include the following:

This will involve surveying the demolition site so as to assess the existing property, adjacent properties and the surroundings. The aim of this activity will be to collect useful information about the condition of the site (such as available space, access to the site, topography of the site, etc.) type of structure to be demolished (such as size), structural members of the property, drainage conditions, adjoining buildings, vehicular traffic conditions and adjoining pedestrians, possible problems on pollution and water, and neighborhood sensitivity with respect to traffic impact, dust, noise and vibration. This will help in determining the most appropriate demolition method and equipment, estimate the amount of demolition material and estimate the total demolition cost. The site and building surveying will be carried out by qualified and certified surveyors.

The existing property is a former clothing factor and there is a possibility of hazardous materials being on site. If these materials are disturbed uncontrollably, they may lead to hazardous exposures for demolition or contractor employees, contaminate the new building to be constructed on site, result to regulatory violations or cause other safety, health and environmental risks. These materials may be building materials or material that may have been used in the previous production processes of clothes. Some of these materials may include building materials containing asbestos, synthetic mineral fibre, copper chromium arsenate, lead based paint, silica, mercury, chlorofluorocarbons and polychlorinated biphenyls (PCBs) (Baldwin, 2016). Any of these hazardous materials will be identified in the building or on site, their conditions and exposure hazards/risks evaluated, applicable federal, state and local regulations determined, and they will be removed and disposed using acceptable methods.

Hazardous Materials Evaluation and Removal

There are different demolition methods, each with unique requirements, costs, benefits and challenges. This being a single storey factory, the chosen demolition method is high reach arm or the conventional top down method. This method has been chosen by considering the location of the building to be demolished, the purpose of demolition, the main building materials and how the debris will be disposed. The main equipment to be used in the demolition process include: hydraulic excavator, jack hammers, sledge hammer, drill, oxyacetylene torch, etc. Some of the equipment are shown below (Kumar, 2016). A long demolition or pusher arm consisting of a telescopic boom will be fitted on a base machine (hydraulic excavator). A hammer will be attached to the pusher arm’s end and used to break up the building (Rodriguez, 2018). Waste materials will be hauled from the site to the identified landfill using articulated trucks. The building will be demolished from the top down.

                                             Figure 1: Hydraulic excavator fitted with a hammer (NPK Construction Equipment, 2015)

                                                                                               Figure 2: Jack hammer (Kumar, 2016)

                                                                                            Figure 3: Sledge hammer (Kumar, 2016)

Chosen Demolition Method and Equipment

                                                                                               Figure 4: Drill (Kumar, 2016)

                                                                                     Figure 5: Oxyacetylene torch (Alamy, (n.d.))

The large elements of the structure removed by the machine will be carefully placed in a designated area where a special ground crew will be breaking them down into small pieces and sort them out for reuse, recycling and disposal. A bucket will be fitted on the hydraulic excavator’s arm to carry the debris to the designated area for sorting, as shown in Figure 6 below. The crew will break down concrete manually using jack hammers and they will cut reinforcements using oxyacetylene torch.

                                                                                  Figure 6: Excavator with a bucket (Aarush, 2018)

Before commencement of actual demolition works, the site will be prepared to ensure efficient and safe operations. The site shall be hoarded using plywood sheets nailed on timber rails (as shown in Figure 7 below) and over 4 m high scaffolds installed with each scaffold having at least one access point. Electricity, gas and water pipes to the site shall be disconnected before commencement of actual demolition. Professionals will also address electrical wiring, HVAC units and plumbing pipes in the existing building. Storage areas for wastes to be reused or recycled and the ones to be disposed will also be identified. The perimeter around the property to be demolished shall be clearly marked and taped off. Floodlights will also be fixed to ensure that the area is adequately lit to facilitate operations during evening hours or at night. Any combustible material shall be removed from the demolition site. Firefighting equipment shall be installed on site and maintained in proper working conditions. An emergency exit route shall also be provided on site to facilitate easy evacuation in case of an emergency. Last but not least, there will be adequate signs placed at different locations on site to give directions or warnings.

Site Preparation

                                                                         Figure 7: Timber hoarding (Collins On Fencing, (n.d.))

All demolition workers, including equipment or plant operators and ground crew, shall be trained about various tasks that they will be undertaking, plant and equipment to be used and how to use them properly, potential hazards and job safety (Occupational Safety and Health Administration, (n.d.)). They will also be trained about communication methods and channels in case of any issues, such as safety hazards or accidents. The training will be done by the safety manager.

Demolition is susceptible to various safety hazards and risks. Some of the hazards include: falling from height, struck by falling materials, slips and falls, sudden collapse of the building, exposure to noise, chemicals and dust, confined working space, collapse of demolition equipment because of insufficient support, etc. (Bhuvaneswari, et al., 2017). This makes safety a very essential element in any demolition work. It is the responsibility of the company to provide safety for its workers. As a result, several measures have been put in place to ensure that the demolition is undertaken in a way that guarantees safety of the demolition workers, nearby buildings or property and the public. Some of the safety measures that have been identified for this work include the following:

The company has prioritized safety in this work to remove or minimize any hazards that are associated with demolition work. This has been done through comprehensive safety planning, which include the following: locating, relocating and securing nearby utilities such as water pipes, drainage network and electricity wires; developing a fire prevention, protection and evacuation plan; hiring a person responsible for emergency medical and first aid services; and undertaking an assessment of possible health hazards associated with the demolition.

The demolition crew will wear appropriate PPE at all times. This includes head (hardhat), face (masks), eye (goggles), hand (gloves) and foot (work boots) protection gear (HomeAdvisor, 2018), hearing protection (earmuffs), respiratory protection, personal fall arrest system (PFAS), overalls and aprons, reflector jackets, etc. There will be adequate training on the suitable type of PPE for use on each demolition, activity, how to use them and why to use them. No person will be allowed on demolition site without appropriate PPE. There will be a safety manger on site to ensure supply of appropriate PPE and total compliance to PPE requirements by the demolition crew.

Safety Measures

The demolition crew shall be trained on various aspects of the work, such as how to choose, use and store PPE, how to identify, remove/avoid and report hazards, and how to respond to an emergency, including giving first aid and calling relevant persons or authorities. The training will be mandatory and undertaken by a qualified safety specialist in a language that is understood by all workers.

All demolition works shall be done under supervision of a qualified person. The company will hire a supervisor who will be on site at all times to ensure that the demolition is carried out in accordance with contract safety specifications.

The demolition work is expected to cause air, noise and vibration pollution that may affect the demolition crew, neighbouring community and the public. The company will minimize some of these environmental impacts through the following methods:

Air and dust pollution: it is likely that a lot of dust will be produced from concrete breaking, debris handling and hauling of debris on the site. The dust will be minimized using water sprays, avoiding dropping materials from the height, and removing waste material from the site as soon as possible before it starts getting blown by wind and creating dust. Air pollution will also be minimized by avoiding burning any wastes on the demolition site.

Noise and vibration pollution: the demolition activities will also produce substantial noise levels and vibration. The noise and vibration will mainly be created from use of powered equipment when breaking structures and dropping debris (Jadhav & Dhawale, 2016). Some of the strategies that will be used to minimize noise and vibration include: fitting effective exhaust silencers on mechanical plant and vehicles, shutting down machines when not in use, and avoiding dropping materials from height.

Waste is a major concern in the construction industry with stakeholders being required to develop approaches of minimizing waste throughout the lifecycle of the project (Ameh & Daniel, 2013); (Reddy, et al., 2018). The industry generates large quantities of waste that need to be managed properly to avoid negative social, economic and environmental impacts (Ghosh, et al., 2016); (Najafpoor, et al., 2014). Developers and contractors are required to adopt environmentally-friendly demolition approaches, such as waste minimization, so as protect the environment (Liu, et al., 2008). The company recognizes that waste minimization and management is essential in promoting environmental conservation and also reducing cost of construction (Lu & Yuan, 2010).  

All demolished materials will be sorted to separate those that can be reused or recycled and the ones to be disposed of the site. Reuse and recycling of building materials helps in reducing wastage and also has economic benefits where the materials can be used for new constructions (Pranav, et al., 2015). After sorting and separating materials that can be reused or recycled, all the remaining demolished building debris shall be loaded on trucks and transported to selected landfills.

Worker Training

The demolition checklist include the following:

Conclusion

This demolition plan is for demolishing the existing single storey former clothing factory to give way for construction of a new two storey apartment block. The plan has been prepared to ensure efficient and safe demolition work. Every element discussed in the plan has to be implemented fully to achieve maximum results. If followed properly, the plan will help to complete the demolition work in an environmentally-friendly and cost effective way and without putting the safety and health of demolition crew, neighbouring community or the public at risk.

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