Various methods used in demolition of buildings

1. TECHNIQUES BEHIND
DEMOLITION OF STRUCTURES

2. INDEX
1. INTRODUCTION
2. OBJECTIVES
3. STEPS BEFORE DEMOLITION
4. DEMOLITION SEQUENCE
5. METHODS OF DEMOLITION
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3. 1. INTRODUCTION.
 In general, demolition can be defined as
wrecking or taking out of any load supporting
structural element of a building (houses,
commercial establishments, and office
buildings) or non-building facility (highways,
streets, and other non- inhabitable construction
projects).
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4. 2. OBJECTIVES.
 Old and damaged buildings ( due to earthquake & 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.
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5. 3. STEPS BEFORE
DEMOLITION.
a. Surveying.
b. Removal of
hazardous
materials.
c. Preparation of
plan.
d. Safety
measures.
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6. SURVEYING
The building survey should cover the following:
• The construction materials.
• The existing use and, if possible, the past uses of the
building prior to demolition.
• Adjoining pedestrian and vehicular traffic conditions.
• The sensitivity of neighbourhood with respect to noise, dust,
vibration and traffic impact.
• Available site area to allow on-site sorting of building
debris.
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7. REMOVAL OF HAZARDOUS
MATERIALS:
Asbestos Containing Material:
• In the case when asbestos containing material are
discovered, specialist contractor shall be employed
to remove such asbestos containing material. The
asbestos waste should be handled, stored and
disposed of as chemical waste in accordance with
the waste disposal regulation.
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8. Soil Contamination Material:
• In the case when possible soil contamination
materials is present, specialist shall be employed to
prepare soil contamination test proposal and submit
such proposal to the environmental protection
department for comment.
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9. PREPARATION OF PLAN:
• A plan showing location of the building to be
demolished, sections of the slopes with ground level
contours and detailed topography, ground removal and
backfilling, distances of adjacent structures from the
building to be demolished.
• A layout plan of all floors of the building to be
demolished, with adequate sections.
• A plan showing the procedure for the demolition of the
building.
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10. • A plan showing the proposed shoring and temporary
support to be provided to the building to be
demolished.
• In the case when powered mechanical plants and
equipment are used, a plan showing the route of
movement of powered mechanical plants and
equipments.
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11. SAFETY MEASURES:
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.
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12. 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 inspected daily and results of the inspection
shall be recorded accordingly.
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13. Electrical Safety:
• A properly connected power source from a local electric
utility supplier or a mobile electricity generator shall be
utilized in demolition sites.
Fire:
• All flammable goods shall be removed from site unless
they are necessary for works involved. Any remaining
flammable goods shall be stored in proper storage
facilities.
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14. METHODS OF DEMOLITION
A. Ball and crane method.
B. Dismantling
C. Pneumatic and hydraulic breaker
D. Explosives
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15. A. Ball and crane method.
• A crane uses awrecking ball, weighing up to 6120
kg, which is either dropped onto or swung into the
element to be demolished.
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16. B. Dismantling.
• Selective or complete demolition of concrete
structures is possible by cutting elements and then
removing them with a crane.
• The cutting process may be by sawing, water
jetting or thermal lance.
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17. C. Pneumatic and hydraulic breaker.
A common piece of equipment used for demolishing
bridgedecks, foundations and pavements is a
hydraulically or pneumatically operated, boom-
mounted breaker.
• A jackhammer is a pneumatic or electro-mechanical
tool that combines a hammer directly with chisel.
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18. • 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 from the excavator,
which is fitted with a foot- operated valve for this
purpose
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19. D. Implosion.
• In the controlled demolition industry, building
implosion is the strategic placing of explosive
material and timing of its detonation so that a
structure collapses on itself in a matter of seconds,
minimizing the physical damage to its immediate
surroundings.
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20. Advantages of explosive demolition.
• Less expensive.
• No ground vibrations.
• Quickest methods.
• Suitable for multi-storyed / high piers, cabins,
distressed piers etc.
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22. CONCLUSION
• It can be concluded that demolishing/ imploing the
building structure will prove very useful,
economical and the quickest for reconstruction.
• Leads to safe and controlled demolition for the
occupants and neighbourhood.
• Development in techniques allows a rapid
demolition with no harm to the environment.
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23. THANK YOU
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