2. INDEX
1. Introduction
2. Objective
3. Step before demolition
4. Method of demolition
5. Building implosion
6. Placing of explosive
7. conclusion
8. Reference
3. Introduction
We know that every structure is designed for a life period.
The existence of the structure after the service life period is very dangerous to its occupant and
surrounding building.
Demolition is the process of tearing down or falling down of a building after its life period with the
help of some equipment or any other method.
When explosive are used for this then demolition process are called as implosion.
4. objective
Old and damaged building (due to earthquake and other various reasons) which are prone to fall
down completely or partially must be demolished before any fatal accident.
When the important structural components like beams and columns become absolutely insufficient
for service then there is no option other than demolishing the building.
When a new structure need to be constructed on the site, the old structure is demolished.
For safety of neighbouring area, a deteriorated building is often demolished.
5. Step before demolition
1. Surveying
2. Removal of hazardous
materials
3. Preparation of plan
4. Safety measures
6. surveying
The building should cover the following :-
The construction material.
Adjoining pedestrians and vehicular traffic condition.
The sensitivity of neighbourhood with respect to noise,
dust, vibration and traffic impact.
Available site to demolition.
Record drawing.
7. Removal of hazardous material
Asbestos containing material – in case when asbestos containing material are discovered,
specialist contractor shall be employed to be removed such material. The asbestos waste should
be handled, stored and disposed off as a chemical waste.
Soil contamination material – in case when soil contamination material is present, specialist shall
be employed to prepare soil contamination test proposal and submit such proposal to the
Environmental Protection Department.
9. Preparation of plan
The Location of building to be demolished.
A layout plan of all floors of the building to be demolished.
The structural support system.
A plan showing the procedure for the demolition of building.
In the case when powered mechanical plants and equipment are used, a plan showing the route of
movement of powered mechanical plants and equipment.
10. Safety measure
Training and communication - Demolition workers,
including plant or equipment operators, shall go through
proper job safety training and be informed of the
potential hazards by attending training sessions as well
as on-the-job training.
11. Equipment maintenance - All equipment shall
be tested and examined before use. They shall
be properly stored and maintained. The
equipment shall be inspected daily and results
of the inspection shall be recorded
accordingly.
Properly marked with exit signs.
Safety measure
12. Fire - All flammable goods shall be removed from site
unless they are necessary for the works involved. Any
remaining flammable goods shall be stored in proper
storage facilities. All furniture, timber, doors, etc. shall be
removed before any welding work is performed. Fire
fighting appliances shall be provided and maintained in
working conditions
Safety measure
14. Piecemeal demolition
A jackhammer is a pneumatic or electro-
mechanical tool that combines
a hammer directly with a chisel.
Jack hammer ->
15. Mechanical method
Ball and crane - A crane uses a wrecking ball, weighing up to 6120 kg, which is either dropped
onto or swung into the element to be demolished.
Ball and crane
16. Mechanical method
Hydraulic breaker
A hydraulic breaker is a powerful
percussion hammer fitted to an excavator for
demolishing concrete structures or rocks. It is
powered by an auxiliary hydraulic system.
17. Explosive demolition
The basic idea of explosive demolition is quite simple.
If we remove the support structure of a building at a certain point, the section of the building
above the point will fall down on the part of the building below that point.
18. Blasting machine blasting cap or electrical detonator
RDX-based explosive compounds expand at a
very high rate of
speed, up to 27,000 feet per second (8,230
meters per second)
Explosive demolition
19. Advantage of explosive demolition
Explosive demolition
Less expensive.
No ground vibrations.
Quickest method.
Suitable for multi-storey / high piers, cabins, distressed piers etc.
24. conclusion
It can be concluded that demolishing/imploding the building structure will prove very useful,
economical and quickest for reconstruction.
Type of demolition method depends upon various factors such as site condition, type of structures,
age of building, height of building and economy.
Explosive demolition is the preferred method for safely and efficiently demolishing the larger
structures.
Development in techniques allows rapid demolition with no harm to the environment.
