• Graeme McKenzie
  • Bijan Samali
  • Chunwei Zhang


Implosion, Collapse, Fragmentation, Ground shock, Dust cloud


For an uncontrolled demolition (terrorist attack) explosives are detonated external to a structure
primarily but not always. On occasions, the terrorist attack is internal to a structure which can also cause the
building to collapse. With a controlled demolition (implosion), explosives are always used internally to a
building. A building is imploded within its’ own design footprint but because of adjacent structures inhibiting it
falls the building might have to be imploded and collapsed outside of its footprint. An oddity is the implosion
of a chimney stack. Chimney stacks because of the physics involved can, whilst collapsing, break into two
separate pieces which causes concern as the trajectory of fall can then become uncontrollable. Several conditions
need to be addressed prior to a demolition as follows:
• Is space available to accommodate the debris pile loose volume generated by the implosion?
• Is the minimum charge weight of explosives being used?
• Will the falling structure cause fragments to impact adjoining structures or can the fragmentation be
• Has consideration been given to dust control?
• After considering structural details of the building does the structure lend itself to collapse through
implosion or should the building be demolished by mechanical means? and
• Does the demolition by implosion prove to be more economical and safer than mechanical means?
A successful demolition occurs if the conditions above are appropriately addressed and executed. The
alternative is to not follow the appropriate conditions and so face three failures that have occurred over the last
20 years in Australia.




How to Cite

Graeme McKenzie, Bijan Samali, & Chunwei Zhang. (2019). DESIGN CRITERIA FOR A CONTROLLED DEMOLITION (IMPLOSION). GEOMATE Journal, 16(53), 101–112. Retrieved from

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