There’s more than one way to skin a cat, and there’s more than one way to demolish a building.
There are many factors to consider before demolition can happen. Things like building material, location, and disposal methods. Here, we’ll discuss four of the common demolition procedures, and in which situations you should use each.
To create an implosion, construction crews put enough explosives inside a structure to eliminate its vertical structural supports. The placement and timing of the explosives is critical, so that each floor of the building falls onto itself, leaving crews with only a pile of rubble to clean up afterwards. Implosions are often used on large structures in urban areas. Ideally, implosions can be directed to tip a building in a certain direction where there are no existing structures. However, this isn’t always possible. When an implosion is performed in a compact urban area, construction companies need to make sure the demolished building collapses straight down — a feat so difficult that few companies attempt it.
Selective demolition involves the removal of walls, floors, ceilings, and exterior building components from a building. If the demolition is of a multiple-story building, jacks are often used to hold up what still remains of the building until it can be completely dismantled. A CNN video shows a 40-story hotel in Tokyo being selectively demolished in a clean, quiet, and effective manner.
Selective demolitions are used primarily to recycle and salvage the building materials. Builders and clients alike often use these types of demolition, although they are often slower than other types.
Crane and Ball
In this demolition procedure, a wrecking ball that can weigh over 13,000 pounds is dropped or swung repeatedly onto the structure. It is vital that the crane operator is skilled, as failure to produce a smooth ball swing could overload the crane.
The Crane and Ball method is often used for concrete and masonry structures. However, this procedure is unsuitable if the building contains rebar or is very large. The crane and ball method is also ineffective if there are limitations on dust, noise, or vibrations.
High Reach Arm
A high, over twenty meters, reach demolition process requires a base machine, usually a tank, engine, excavator, or counterweights. The demolition itself is performed by the three-section demolition arm or by a telescopic arm equipped with a primary tool like crushers, shears, or hammers. Factors like the height and shape of the structure, as well as the site conditions, require different considerations when using the demolition arm.
This method can be used for reinforced concrete, masonry, and mixed-material structures. Here’s an example of a Caterpillar 385C high reach demolition of a several-story building.
If you’re interested in reading more about building demolition or construction related topics, check out the H Brown Machine Shop blog