Demolition involves the dismantling or destroying of buildings or structures through pre-planned and controlled methods. It contrasts with deconstruction, which carefully preserves elements for reuse. Demolition plans outline the sequence, equipment, safety precautions, and disposal of debris. Larger demolitions may use wrecking balls, hydraulic equipment, or implosions, while smaller buildings are often dismantled manually or with machines. Proper demolition requires surveying the building, investigating structures, and ensuring neighboring safety.

5. WHAT IS DEMOLITION
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6. Demolition is the DISMANTLING,
RAZING, DESTROYING or
WRECKING any building or structure
or any part of building by PRE-
PLANNED and CONTROLLED
methods.

8. Demolition is the tearing-down of
buildings and other structures.
Demolition contrasts with
deconstruction, which involves taking
a building apart while carefully
preserving valuable elements for re-
use.

9. For small buildings, such as houses, that are only two or three stories
high, demolition is a rather simple process. The building is pulled down
either manually or mechanically using large hydraulic equipment:
elevated work platforms, cranes, excavators or bulldozers.

10. Larger buildings may require the use of a wrecking ball, a heavy weight
on a cable that is swung by a crane into the side of the buildings.
Wrecking balls are especially effective against masonry, but are less
easily controlled and often less efficient than other methods.

11. Code of practice for Demolition
Plan
When preparing plans for demolition
works, reference should be made to the
relevant regulations in the Buildings
Ordinance and the Code of Practice for
Demolition of Buildings issued by the
Buildings Department (BD)

12. Scope of the CoP of
Demolition
Outline good practices for PLANNING and
IMPLEMENATION of demolition of various
building works aiming at minimizing the risk of :
– damage to people and properties of the PUBLIC;
– endanger the health and safety of SITE
PERSONEL;
– damage to the neighborhood ENVIRONMENT.

14. Building appraisal by means of
– Building Survey
– Structural Survey
– Demolition Plan & Stability
Report including
Calculation
– Utilities
– Hazardous materials

16. Demolition Plan
• location plan
• layout plan
• structural plan
• procedure plan
• plant routing and structural alteration
• precautionary measures plan
• shoring plan (outside)
• shoring plan (inside)
• debris disposal plan
• Special safety considerations
• Traffic
• Post-demolition arrangement

18. A. Record Drawings
B. Survey Items
C. Special Structures
D. Investigation and Testing

19. Record Drawings
1.Studying the record layout,
structural framing plans and structural
details.
2.Checking if any unusual detailing
that may cause abnormal structural
behaviour during demolition.

20. Survey items
• The structural materials used;
• The original structural system employed;
• The method of construction;
• Condition of structural elements;
• The structural conditions of adjoining
structures;
• The presence of continuous structures that
may be truncated by the demolition

21. Special Structures
• The correctness of structural information
available;
• Any unconventional structural elements;
• The possibilities of structural modification to
enable efficient demolition traffic during
demolition;
• Any limitation on shoring and other
temporary supports.

22. Investigation & Testing

23. If no structural details are available, the
structural survey shall include:
1. Site measurement;
2. Field testing;
3. Expose some key structural elements

24. Demolition Plans
• The construction and condition of the building
to be demolished, including sections showing
slopes and ground supported by it, and all
affected buildings, structures, streets, land and
services
• The existing nature of the site and surrounds
(including an accurate survey plan with ground
level contours and sections showing slopes and
ground supported by the building to be
demolished) and all necessary removal of ground

25. Demolition Plans (cont.)
• The sequence, equipment and procedures for the
demolition works
• The support to be provided to the building to be
demolished and any slopes and ground supported by it
and all affected buildings, structures, streets, land and
services at each stage of the demolition works
• All precautionary measures for the protection of the
public including dust screens, catch fans, hoardings and
covered walkways
• The support to be provided to all affected buildings,
structures, streets, land and services at each stage of
the demolition works

26. Methods of Demolition
• Top-down manual
• Top-down machines
• Mechanical by hydraulic crusher with
long boom arm
• Wrecking ball
• Implosion
• Others: non-explosive demolition
agent; saw-cutting; cutting and lifting;
mechanical demolition; thermal
lance and water jet

38. Special Structures
• Precast concrete structures
• Prestressed concrete structures
• Statically determinate structures
• Composite structures and steel structures
• Cladding walls
• Hanging structures
• Oil storage facilities
• Marine structures
• Underground structures
• Structures supporting ground or sitting on slopes

39. Comparing Top-down manual and
Top-down
machines methods
• Manual: by jack (or pneumatic) hammers and
oxy-acetylene torch
• Machines: by percussive breaker, hydraulic
crusher and excavator arm
• Similar Sequence: cantilevered slabs and
projected elements – roof – cantilever beams –
secondary beams – main beams – nonload
bearing walls – columns and load bearing
walls.
• Machines support and lifting: temporary ramp
construction