The Demolition Method in the World of Construction
A demolition refers to the controlled and preplanned removal of a building structure. An old building is destroyed in a controlled manner when its design life has expired via demolition.
Two things are important for demolition here, one is the design life, the other is the destruction of the old building in a controlled manner, and the third is choosing which demolition technique is best.
Both of these factors contribute significantly to the demolition of a building. In the process of demolition, it is important to ensure that the surrounding area is not damaged or impacted by the process.
Demolition Plan
A demolition plan is drawn up based on building survey results for approval of demolitions. As part of the application for demolition approval, the plan is submitted to the local authority.
The location of the building is shown on the plan. A measurement is taken of the height, structural integrity, and extent of damage to the building, as well as the height and details of structures around the building.
The surrounding buildings are safe and provide shopping opportunities. The various steps of demolition and the safety measures involved. You have to handle and dispose of debris, and supervise the site, etc. Determining the layout, demolition plans, and use of machinery are all required.
Key Factors of Demolition Method Selection
Demolition Type
Different types of structures require different demolition methods. Various methods of demolition are used when removing different types of structures.
Structure Size
If the structure is small, then no special demolition method is needed. Large structures require special demolition techniques, which can be done by hand.
Duration
You can consider the time frame available for demolition as you choose the method.
Demolition Techniques
Wrecking Ball Method
A crawler mounted crane hangs a steel ball weighing .5 to 2 tons in this method of demolition. Concrete or machinery is broken when these steel balls impact. There are two techniques in this method: vertical and swinging wrecking balls.
The wrecking ball must be handled by an experienced operator. It is necessary for cranes to be able to move around the building being demolished. During the demolition process, first the building's interior must be torn down to make the necessary space for demolition.
Thermic Lance Technique
By melting concrete and reinforcement steel at high temperatures, this method of demolition breaks them. Using this method, the temperature can be raised from 2000 to 4000 degrees centigrade.
There are wires of aluminum alloy or iron alloy kept in pipes having a diameter of 14 to 18 mm. As acetylene gas flows between the wires, it ignites the metal lance. Oxygen is produced when the acetylene gas is converted to oxygen and the metal lance burns.
It is resulting in a gradual melting and shattering of the concrete and steel reinforcement. There is an increasing trend toward using powered lances instead of metal lances. If you are taking this approach, then it will make safety a priority. When other demolition methods are not possible, this method is used.
Pressure Jetting Method
A high pressure water jet is released from the nozzle onto the concrete surface during this demolition method. Plain concrete is cut by this jet due to abrasion.
Garnet or steel particles are used to cut the concrete with an abrasive water jet. A nuclear power plant demolition method based on this technique was developed. Whenever possible, water jets should be used with recycled and reusable water.
To learn more, watch the following video tutorial.
Video Source: Interesting Engineering
Manual Demolition
Demolition by hand is also called manual demolition. Small structures in densely populated areas can be easily destroyed with this method of demolition. Construction structures are demolished manually by laborers. Since the site is crowded, large machinery cannot be brought there.
