for the subject offered in GTU, BCT, ace, cm module 4 demolition of the structure for the 3rd sem & also for the 6th sem subject and for the master of construction management

1. Civil Funda By:- Balar Sir

2. Contents
What is Demolition?
Planning For Demolition
Types of structural demolition
Methods Of Demolition
Precautions Before and During Demolition

3. • Demolition means dismantling, destroying or wrecking any
building or structure or any part which is pre-planned and
handled with controlled methods.
• Demolition methods depending…
– area where it will be held on
– Time availability.
– Types of building material,
– the purpose of the demolition
– the way that debris is going to be disposed.

5. To dismantle something means you take it apart in a process, like
piece by piece.
To demolish something (demolition is the noun) means you destroy it.
Less care and probably not much method.

6. • The structures already passed their design life.
• need to be reconstructed, for safety and operational requirements.
• The old structures need demolished for replacement by new.
• Small structures can be demolished by manual.
• machinery and advanced techniques are required for big structures.
• Advanced techniques are also required for faster demolition and
demolition in confined areas.

7. • Before beginning of actual work for demolition careful
study shall be made of the structure which is to be pulled
down and also of all its surroundings.
• For that, its include following steps….

8. 1.
• Building Appraisal and Demolition Plan
2.
• Utilities
3.
• Hazardous Material

9. 1.Building Appraisal and Demolition Plan
• The study of the structure, before demolition, carried out by
surveys which include…
• General Survey
• Structural Survey, with photographs or videos taken for future
reference.
• The demolition plan also accompanied by a report of structural
calculations, stability of building, all affected buildings,
structures, streets, land and services.

11. 2.Utilities
• The common utilities encountered before demolition include…
– Electricity,
– Water & Gas,
– Telecommunication,
– Drainage & its accessories,
– Overhead & Underground Cables.
• The DP shall ensure that during the demolition, no existing utilities is
present on demolition sites, are affected by the demolition operation.

12. 3.Hazardous Material
• If hazardous materials, such as…
– asbestos containing materials,
– petroleum contamination,
– radioactive contamination, exists in the building
 further investigation and removal of such hazardous material or
contamination by specialist shall be considered.

13. Asbestos Material
Soil Contamination

14. • There are multiple types of demolition procedures used to take down
structures.
• The choice of method depends on the…
– project conditions,
– site constraints,
– sensitivity of neighborhood
– availability of equipment.

16. 1. Manual Method
• carried out as top down, in general, from the roof to
ground.
• sequence of demolition may vary, depending on site
conditions and structural elements to be demolished.
• For RCC buildings, jack hammers used to break down the
concrete.

17. Fig: Demolition By Manual Method
Source:www.konkret.info.pl

18. Pneumatic hammer

19. 2. Top Down — By Machines
• same as the top down manual method, except that most of
the demolition is done by Machines.
• The demolition begins with the lifting of the mechanical
Machines on to the building top floor.
• Step by step demolish building component starting from
slab, beam, column etc.

20. Sequence of demolition - top down with Machines
1.Demolish slab & beam 2.Continue demolishing slab &
beam

21. 3.Access ramp to lower floor 4.Demolition of interior column

22. 5.Cut external wall &
column
6.Pull down wall
section

23. Step 1
Step 2
Step 3

25. 3. Hydraulic Crusher
• The crusher attachment breaks the concrete and the
reinforcement by the hydraulic thrust through the long
boom arm system.
• Can be operated from the ground outside the building.
• Also suitable for dangerous buildings, silos and other
industrial facilities.

27. Fig: Hydraulic Crusher with Long Boom Arm
Source: www.jewellattachments.com

29. High Reach Demolition Excavator
Hammer
ATTACHMENTS
Grapples
Multiprocessor
Pulverizers Buckets
Shear

30. 4. Wrecking Ball
• The wrecking ball consists of a crane equipped with a steel ball.
• The destruction of the building is by the impact energy of the steel
ball suspended from the crawler crane.
• Operates from outside the building.
• This is suitable for silos and other industrial facilities.
• The operation requires substantial clear space.

31. Wrecking Ball Crane
• Produce Repeated Vibration
• Less Control On Moving
Ball
• More force required
• Can’t be used on Steel
structure
• Waving action of ball
leads to heavy loss
• Ball is heavy so give
good impact but also
become uncontrollable
• Different ball sizes to be
used on different
structures

32. Wrecking ball at rest (up to 6120 Kg.)
Swinging the wrecking ball

35. WRECKING BALL (SWING + TOP DOWN)

36. WRECKING BALL + CRUSHER

37. Explosive Demolition
• High Risk Factor
• Time Taken
• Produce Distortion
• Expensive
• Chances of error
• Need of experts
• Error may leads to
• No demolition
• Loss of life's
• Quick
Demolition

38. 5. Implosion
• 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.
• In this removes critical supports so that the building can
no longer withstand the force of gravity and falls under its
own weight.

39. • For Steel support structure, use the specialized explosive
material Like cyclo-tri-methylene-tri-nitramine, called
RDX for short.
• RDX-based explosive compounds expand at a very high
rate of speed, 8,230 meters per second.

42. Process of Implosion

43. Other Methods
• Non Explosive Demolition Agent
 Non Explosive Demolition Agent (NEDA) is a static demolition agent.
When the reaction takes place in a confined drill hole, the NEDA generates
an expansive pressure to crack and break concrete and stone.
 The NEDA is a suitable application in a restrictive environment where
noise, flying debris and vibration are less tolerated.
 NEDA may be used on foundation works, pile caps or structures that are
fully supported.
 When used in rock, NEDA should be contained within strong, flexible,
impermeable bags to prevent uncontrolled entry into rock joints.

49. SAFETY PRECAUTIONS
 Demolition
 Dismantling.

50. Precautions Before and During Demolition
• Precautions before and during demolition…
– The demolition shall not be start until precautionary measures have
been inspected and approved.
– Inform adjoining neighbors prior to the demolition, so that they may
close windows or take other measures.
– all electric cables or apparatus which are liable to be a source of
danger, other than a cable or apparatus used for the demolition
works shall be disconnected.

51. –The work shall be under the continuous supervision of the
demolisher or often experienced foreman.
–demolition executed storey by storey commencing at the roof and
working downward.
–Notices lettered displaying the words “WARNING DEMOLITION IN
PROGRESS” to be fixed to the hoarding or security fence.
–Dust creating material, unless thoroughly dampened shall not be
thrown or dropped from the building but shall be lowered by hoisting
apparatus or removed by material.

52.  WALKWAYS:
Walkways shall be provided for the use of the workmen who shall
be instructed to use them and all such walkways shall be kept
adequately lighted, free from debris and other materials.
 CATCH PLATFORMS
In demolition of exterior wall of multistoried structure, catch
platform of heavy planking shall be provided to prevent injuries to
the worker working below and to the public, when the external
walls are more than 20 m in height.

53. •HOARDING isolates the demolition site from the public,
thus preventing unauthorized access and trespassing.

56. PROTECTIVE SCREENS

57. TRAINING AND COMMUNICATION
 Demolition workers.
 plant or equipment operators
 working at heights
 working in confined spaces
 working with lifting appliances
 use of personal protective equipment
 handling of chemicals
 health hazards in demolition works
 safe operating zones.

58. ELECTRICAL SAFETY FIRE SAFETY

60. DEBRIS AND WASTE HANDLING

61. Debris shaft formed by
opening
temporarily cut on floor
slab
Debris collection area at ground floor under the
debris shaft

76. WIRE SAW CUTTING

77. THANK YOU