DEMOLITION OF BUILDINGS: INTEGRATED NOVEL APPROACH

Conference on: “Trends and Challenges of Civil Engineering in Today’s Transforming World”
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29th March, 2014, Civil Engineering Department S.N.P.I.T. & R.C., Umrakh
DEMOLITION OF BUILDINGS: INTEGRATED NOVEL
APPROACH
Hardik Patel1
, Ashish H. Makwana2
, Jayeshkumar Pitroda3
, Chetna M. Vyas4
Final Year Student, ME C E & M., BVM Engineering College, Vallabh Vidyanagar, Gujarat, India 1
Final Year Student, ME C E & M., BVM Engineering College, Vallabh Vidyanagar, Gujarat, India 2
Assistant professor, Civil Engineering Dept., BVM Engineering College, Vallabh Vidyanagar, Gujarat, India 3
Assistant professor, Civil Engineering Dept., A.D. Patel Institute of Technology, New Vallabh Vidyanagar,
Gujarat, India 4
Abstract: Every civil engineering structure is designed for a certain life period generally 100
years. After that the existence of a structure is very dangerous and unstable, which may cause
a severe impact and be a cause of many deaths. So removal of such structures with proper
safety measures has got great importance. Before any demolition of any type is employed in
an area, it is vital that the rescue phase has ended completely. The rescue teams must have
given clear information to the contractors that their rescue phase is finished in the selected
area, since any demolition work carried out may reveal survivors. Such situations are highly
sensitive and must be respected. A major disaster has an economic effect on the local region
since the loss of buildings, lifelines and infrastructure results in a slump in the local
economy. It is therefore important to boost the economy by employing as much local
expertise and workforce as possible. This creates a unity in rehabilitation in the community
and results in a more stable recovery. Due to this scenario, the demolition work should be
carried out by a consortium, especially set up to do the work rather than commissioning the
work to individual companies. This consortium must be set up in regions of high seismic risk
to ensure rapid formation after a disaster. This will combat the eventual competitiveness of
the large financial investors in the community which could result in a monopoly controlled by
certain individuals. It would therefore be preferable to have a local demolition joint-venture
to generate the needed local income after a disaster. There will, however, be a certain need
for outside managerial and consultancy aid, especially in the developing countries, and this
must be acknowledged and respected. The cooperation with the outside aid must be extensive
and at a high level in conjunction with the local representatives so as to maintain as much of
the local culture and style as possible. The outside consultants must be cautious when
introducing major resources, such as machinery, into the post-disaster phases since this may
be seen as taking work away from local resources.
Keywords: Consortium, Demolition Work, Rescue phase, Safety measures

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I. INTRODUCTION
A. Definition
Demolition of any structure is the process of destroying down or falling down or
collapsing down of large buildings after its useful life period with the help of some
equipment or other method with a legal procedure followed by the consent of the local
authority.
B. Overview of Demolition of Buildings
Demolition work is to be performed safely and with a number of different steps involved
before and during the execution of a demolition process. The various steps involved before
the demolition process includes surveying the site of demolition, removal of hazardous
materials, if any, and preparation of demolition plan with techniques to be implanted, stability
report and the precautionary safety measures to be taken from the workers and the
surrounding. Equipments used for these demolition activities are like sledge hammer or
rammers; excavators, bulldozers, tearing balls, etc. and main explosives used are like
dynamites and RDX. When explosive are used for the demolition, it is known as Implosion,
which is generally preferred for high and tall towers.
Any demolition activity to start with, there are many steps that need to take place
forehand including but not restricted to performing asbestos abatement, removing hazardous
or regulated materials, obtaining necessary permits from the authority, submitting necessary
notifications, disconnecting utilities, and development of site-specific safety and work plans
for the workers as well as the surroundings with a detailed planning of every stage with a
working strategy.
The existence of the structure after the service life period is over is very dangerous to its
occupants and surrounding buildings. The building act usually based on the provisions that
enable in charge authorities to control demolition works for the protection of public safety
with their belongings and to ensure adjoining premises and the site are made good on
completion of the demolition.

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Figure 1: Tearing-down of buildings and other structures by pre-planned and controlled methods
Source: https://www.google.co.in/#q=demolition+of+buildings+images
C. Factors affecting the evaluation of Demolition Methods
II. NEED FOR DEMOLITION OF STRUCTURES
 Many structures are being erected nowadays, but the prime locations are hard to find,
therefore setting up these infrastructures are becoming more and more difficult.
 Old buildings are demolished, excavated or destroyed to pave the way for a new
architectural structure to be built.
 Demands for modernization and improved comfort.
 Redevelopment for inner urban areas.
 Rapid technological changes within industry require even more efficient plant premises
and this necessitates at least partial demolition.
 If a building is being a threat to safety for adjacent buildings, it should be demolished as
early as possible.
Structural Form
• Scale of construction
• Location of building
Range of Demolition
• Condition of building
• Existence of local structures and restrictions
Existing Environmental Requirements
• Specific accident risk
• Permitted noise, vibration, dust

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The consequences of the above will be increased demand for the further technological
development of demolition methods and equipments and their levels of efficiency.
III. PLANNING FOR DEMOLITION
A. Building Appraisal and Demolition Plan
B. Utilities encountered in Building Demolition
Building Survey Structural Survey Demolition Plan Stability Report
including
Calculations
Electricity Water Gas
Telecommunication Drainage
Overhead and
Underground Cables
Railway Tunnel and
its accessories, such
as vent shafts
Sewage Tunnel and
its accessories
Disused Tunnel

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IV.PREPARATION FOR DEMOLITION
 Thoroughly inspect the premises, sites, surroundings, neighbouring buildings that could
be affected by the intended demolition work.
 Investigate the environmental requirements/restrictions and whether there is any
potential risk to life and property.
 Check the stability of framed and roofed structures.
 Check the thickness of all walls and identify load bearing walls.
 Structural or Geotechnical calculation to support adjoining properties.
V. DEMOLITION SEQUENCE
The demolition contractor should adopt a method of work which:-
 Gradually reduces the height of the building; and
 Arranges the deliberate, controlled collapse of the building or structure so that work can
be completed at ground level.
Demolition sequence shall be determined according to actual site conditions, restraints, the
building layout, the structural layout and its construction. In general, the following sequence
shall apply:
 All cantilevered structures, canopies, verandas and features attached to the external walls
shall first be demolished prior to demolition of main building and its internal structures
on each floor.
 When demolishing the roof structure, all lift machine rooms and water tanks at a higher
level shall be demolished.
 Demolition of the floor slabs shall begin at mid span and work towards the supporting
beams.
 Floor beams shall be demolished in the order as follows: Cantilevered beams, Secondary
beams, Main beams. In the case when structural stability of beams are affected, e.g., due
to loss of restraints, the affected beams shall be propped prior to loss of support or
restraint.
 On-load bearing walls shall be removed prior to demolition of load bearing walls.
 Columns and load bearing walls shall be demolished after removal of beams on top.

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TABLE I: - LIST OF DEMOLITION METHODS AND THEIR APPLICATIONS
Method Primary Application Disadvantages Reference
Breaker, hand
held
Crushing of thin walls, brackets and
floor slabs in connection with
repairing and rebuilding, used where
access and working conditions are
poor and strict environmental
standards set.
Limited Cutting thickness and range,
unsuitable where the reinforcement bars
are to be retained. Heavy equipment, best if
supported on tackle or the like. Use of face
mask necessarily
Carlo De Pauw,
Erik K.Lauritzen,
“Disaster Planning,
Structural
Assessment,
Demolition and
Recycling”, Taylor
& Francis, London.
Breaker,
mounted
Demolition of concrete columns,
beams, balcony walls and floor slabs
in connection with environmentally
sensitive projects. Partial demolition
of concrete.
Cutting of reinforcement bars can cause
difficulty, not suitable for work where bars
are to be retained. Use of face mask
necessarily
Hammering,
hand held
Cleaning of demolition boundaries
in connection with partial demolition
and reparation. Exposure and
cleaning of reinforcement. Other
minor concrete demolition tasks.
This method is expensive as it causes much
noise, dust, vibrations and physical damage
to the user. Must use a face mask, ear plugs
and respiratory equipments.
Danish recommendation pr. Day: hour
Hammering,
mounted
The larger machines apt for larger
projects in a suitable range. Smaller
machines more appropriate for
minor tasks in repairing and
rebuilding of concrete structures.
Hammering involves environmentally
damaging aspects including dust and noise;
larger machines also vibrations. Access
must be large enough for the machine.
Remote controlled equipment
recommended to reduce hazards, ear plugs
and face mask necessary
Bursting,
explosives
Demolition of massive non-
reinforced concrete structures and in
environmentally cautious areas.
Requires pre-work with diamond boring
machine. Crack development is difficult to
control.
Blasting,
explosives
Holes in concrete slabs more than 30
cm thick. Demolition of reinforced
concrete in large quantities. Mini-
Blasting for reparation and
rebuilding, and the exposure of
reinforcement bars, where the bars
must be used again for recasting, eg.
Concrete columns and brackets.
This work requires special education and
licenses. Some work to clean fracture
boundaries with handheld hammering or
water jet is necessary after blasting.
Blasting, non-
explosives
Demolition of larger concrete
structures, eg. Non-reinforced
foundations
Considerable reaction time is needed for
agents to expand properly. The chemical
reaction necessitates personal protection
Cutting and
drilling
diamond
Holes in concrete slabs. Demolition
work where clean boundaries are
necessary. In combination with other
methods.
High noise levels and water reuse.
Cutting and
drilling, fuel
oil flame
Cutting and drilling of strong
reinforced concrete.
Requires special education and experience.
Fire risk
Water jet
Surface treatment of reinforced
concrete. Used for the removal of
layers, drilling and cutting
Requires certain safety regulations.
Considerable water reuse. Equipment
should be mounted. High risk and physical
loads if used hand held

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VI.DEMOLITION TECHNIQUES
A. Demolition using hand held tools
This method is usually used for small demolition volumes and often as preparatory work
for another demolition methods. It is highly labour intensive, slow and expensive. The most
common type of hand held equipments used are hand hammer and stone chisels. Hydraulic
hammer or pneumatic hammer is used for breaking away the concrete. It is effective in
localized and narrow space.
Figure 2: Hydraulic Hammer
B. Demolition using a wire saw cutting
First developed in the stone quarry industry and they have been used in concrete
demolition work to cut reinforced concrete since the early 1980s. Able to cut concrete of
almost any thickness. This makes them the ideal tool for heavy demolition like bridges, dams
and concrete structures. They create less dust, noise and vibration, making them ideal for
demolition work in or close to residential structures.
Figure 3: Wire Saw Cutting Machine
C. Demolition by machine
A common method used in India for demolition of structures. Used in large demolition
volumes structures. When demolition by hand, tool is time consuming and unsafe, this
method is adopted. Demolition of buildings by machine can be done by using wrecking ball
and hydraulic crusher.
1) Wrecking Ball: Wrecking ball generally comprise a drag-line type crawler chassis fitted
with a lattice crane jib. It is suspended from the lifting rope and swung by the drag rope.

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Figure 4: Wrecking Ball
Figure 5: Vertical Drop
Vertical Drop: Free falling of the wrecking ball onto the structure.
Figure 6: Swing in Line
Swing in Line: Winging of the ball in-line with the jib. A second dragline will normally
connect to the ball horizontally to control the ball motion.

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2) Hydraulic Breakers: It is a powerful percussion hammer fitted to an excavator for
demolishing concrete structures or rocks. Powered by an auxiliary hydraulic system from
the excavator, which is fitted with a foot-operated valve for this purpose. Hydraulic
breakers with long arm extension is used for high rise buildings. The crusher attachment
breaks the concrete and the reinforcement by the hydraulic thrust through the long boom
arm system. Debris may be used to build up a platform for the excavator to extend the
range of reach. It is important that the debris is densely compacted to support the
operation of the excavator. The platform must be flat and slope must be stable.
Figure 7: Wrecking Ball
3) Methodology:
a. Sequence of Demolition of Slabs and Beams
Step 1: Demolition of Slabs and Beams

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Step 2: An access Ramp of Steel Structural Frame to allow Machine to climb down to the
Next Floor Below.
Step 3: Cutting the Exterior Walls in Sections and Pre-weakening of Columns (Cutting
should be careful to minimize debris falling outside).
Step 4: Machine should be used to brace the wall section while cutting Reinforcing bars
connecting the Wall Section.
Figure 8: Sequence of Demolition of Slabs and Beams

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b. Sequence of demolition of Brick in-fill wall and exterior columns
Brick-in-fill wall: The in-fill bricks shall first be manually removed from the top layer down
by pushing it from outside. Work platforms erected outside the building may be used for this
operation. After the in-fill bricks are removed, the reinforced concrete frame may be
demolished by dismantling the framing sections.
Figure 9: Demolition of Brick in-fill wall
Source: Canton Public Library: http://town.canton.ma.us/Library/lbc/Photos/construction/sep02.htm
Exterior Column: The excavator arm with wire or hydraulic crusher attachment shall be used
to brace the column. Pre-weakening shall be performed at the bottom of the columns. After
pre-weakening, the column shall be pulled down in a controlled motion into the building by
the excavator arm.
Figure 10: Demolition of Exterior Columns

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4) Limitations:
Only highly skilled and experienced crane operators should be used on ball and crane
demolition projects.
Smoothness in controlling the swing of the ball is important since missing the target may
tip or overload the crane and a mild swing-back may cause the ball to hit the boom.
The size of the building that can be demolished with this method is limited by crane size
and working room, including proximity to power lines.
This form of demolition creates a great deal of dust, vibration and noise.
D. Demolition using implosion
Implosion is the direct opposite of explosion. Explosion - a charge goes off and
something solid is ripped into a lot of little pieces that fly all over the place, making everyone
in the vicinity take cover. An implosion is the strategic placement of explosive charges that
actually destroy the structural integrity of the building causing it to fall not out, but in upon
itself (this is often referred to as falling into its own footprint).
The basic idea of explosive demolition is quite simple: If you remove the support
structure of a building at a certain point, the section of the building above that point will fall
down on the part of the building below that point. If this upper section is heavy enough, it
will collide with the lower part with sufficient force to cause significant damage.

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The explosives are just the trigger for the demolition. It's gravity that brings the building
down.
Imagine wooden blocks stacked on top of each other; pull out a few of the bottom blocks
and the structure falls by gravity. Explosives are used to start the destruction, but gravity
takes over and completes the job.
For concrete columns traditional dynamite is used.
When the chemical is ignited, it burns quickly, producing a large volume of hot gas in a
short amount of time. This gas expands rapidly, applying immense outward pressure (up to
600 tons per square inch) on whatever is around it.
Demolishing steel columns is a bit more difficult, as the dense material is much stronger.
For buildings with a steel support structure, RDX is used as the specialized explosive
material.
E. Demolition using dismantling
By cutting concrete elements and then removing them by crane, the demolition of an
entire concrete structure may be carried out with a minimum of noise, dust and impact on
surrounding structures.
This may be done by the following methods.
1) Water-jetting
-Minimizes and eliminates dust and fire hazards.
-Can be used to cut both, straight lines and contours.
-Requires the use of an abrasive and water-catching system during the cutting process.
2) Thermic Lance
A Thermic lance is a tool that burns iron in the presence of pressurized oxygen to create
very high temperatures for cutting.

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F. Demolition using Mechanical and chemical bursting
Both mechanical and chemical pressure bursting split the concrete, either with a splitting
machine operating on hydraulic pressure provided by a motor in the case of mechanical
bursting, or through the insertion of an expansive slurry into a pre-determined pattern of
boreholes in the case of chemical bursting. The split concrete is then easily removed, either
by hand or by crane.
VII. CHANCES OF ACCIDENTS WHILE DEMOLITION
Accidents have been caused during the demolition by:
1) Persons falling from high, unprotected workplaces and through openings;
2) Persons being struck by falling objects;
3) The building collapses suddenly and unexpectedly;
4) Insecure materials on the structure;
5) The plant being used on elevated slabs without proper precautions being considered.
VIII. SAFETY MEASURES WHILE DEMOLITION
1. Precautions must be taken before and during demolition in accordance with AS2601-2001,
„The Demolition of Structures‟.
2. It is advisable to inform adjoining neighbours prior to the demolition so that they may
close windows or take other measures.
3. Before demolition is commenced, and also during the progress of such work, all electrical
cables or apparatus which is liable to be a source of danger, other than a cable or apparatus
used for the demolition works shall be disconnected.
4. During the progress of demolition, the work shall be under the continuous supervision of
the demolisher or of an experienced foreman.
5. Unless otherwise expressly approved, demolition shall be executed storey by storey
commencing at the roof and working downward.
6. When the demolition site adjoins a street or public walkway, a 2.4 meter high solid
hoarding shall be erected.
7. The demolished material shall not be allowed to remain on any floor or structure if the
weight of the material exceeds the safe carrying capacity of the floor or structure.
8. 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 chutes.
9. Chutes shall be completely enclosed and a danger sign shall be placed at the discharge end
of every chute.

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IX.CONCLUSION
 Type of demolition method can depend upon various factors such as site condition, type of
structures, age of building, height of the building and the economy.
 Explosive demolition can be preferred method for safely and efficiently demolishing the
larger structures.
 For small buildings, that are only two or three stories high, demolition can be a simple
process.
 While demolition by any method, the safety measures as precautions should be taken.
REFERENCES
[1] Carlo De Pauw, Erik K.Lauritzen, “Disaster Planning, Structural Assessment, Demolition and Recycling”,
First edition 1994, ISBN 0-203-62648-6 Master e-book ISBN, ISBN 0-203 63038-6 (Adobe eReader
Format), ISBN 0 419 19190 9 (Print Edition), © 1994 RILEM, Taylor & Francis, London.
[2] CBS Statline (2008a), Residential buildings by region. http://statline.cbs.nl
[3] CBS Statline (2008b), Changes in the dwelling stock. http://statline.cbs.nl
[4] Code of practice for Demolition of Buildings by Building Departments of Hong Kong in 2004.
[5] Erik K. Lauritzen, “Demolition and Reuse of Concrete and Masonry”, First edition 1994, ISBN 0-203-
62687-7 Master e-book ISBN, ISBN 0-203-63071-8 (Adobe e-Reader Format), ISBN 0 419 18400 7 (Print
Edition), E & EN SPON, Chapman & Hall, © 1994 RILEM, 24–27 October 1993, Odense, Denmark.
[6] Gruis, V. & N. Nieboer, (2004), “Asset Management in the Social Rented Sector”, Dordrecht (Kluwer).
[7] Itard L. & F. Meijer, 2009, “Towards a sustainable Northern European housing stock”, Amsterdam (IOS
Press).
[8] Jonge, T. de (2005), “Cost effectiveness of sustainable housing Investments”, Delft (DUP).
[9] Klunder, G. (2005), “Sustainable solutions for Dutch housing: Reducing the environmental impact of new
and existing houses”, Delft (DUP).
[10]Kohler, N. & U. Hassler (2002), “The building stock as a research object in Building Research &
Information”, 30(4).
[11]Ljubljana.Awano, H. (2005), “Towards the sustainable use of building stock”, Paris (OECD).
[12]MVROM (2008), INFO-Wonen, http://www.vrom.nl/infowonen
[13]Thomsen A. & K van der Flier (2002), Updating the Housing Stock, The Need for Renovation Based-
Approaches, in “Housing Cultures – Convergence and Diversity”, ENHR Conference 2002, Vienna.
[14]Thomsen A. (2007), “The New Building Assignment: Old Stock, New Markets”, Era build Event" 2007,
29-30 October 2007, Amsterdam (TU Delft).
[15]Prof. Chimay Anumba, Dr. Barbara Marino, Prof. Arie Gottfried, “Health and safety in refurbishment
involving and structural instability”, (Research 204).
[16]Tom Harris, “An article on How Building Implosions work”.
[17]Wassenberg F. (2006), “Motives for Demolition, in: “Housing in an expanding Europe”, ENHR Conference
2006.
[18]Y.Kasai. “Demolition Methods and Practice”, Proceedings of the Second International RILEM Symposium,
Tokyo, Japan. Chapman and Hall, London, UK 1988.

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