Collapsed Structures Flashcards
Two broad causes of structural collapse
Natural Causes
Human Causes
Natural Causes of structural collapse
Earthquake
Hurricane
Lightning
Flooding
Subsidence
Human causes of structural collapse
Renovation
Accidental impact
Arson
Terrorism (aeroplane, vehicle, explosion)
Accidental gas explosion
Two broad types of building to consider for structural collapse
Framed buildings Frame of steel or RC Public buildings eg office or hospital Greater resistance to collapse Damage localised
Unframed Walls carry loads Traditional Brick & joist Wall damage can lead to extensive collapse
Three collapse categories or types
Internal
External
Total
Types of internal collapse
Pancake
Failed load bearing wall or upper floor.
Upper Floor falls horizontally or pancakes upon lower floors causing those floors to potentially also fall
Lean-To
Failed load bearing wall or Beam fails at one end.
Floor forms a triangular void
V-Collape
Floor fails in the middle due to heavy load or collapse from above. creates 2 voids outside the V
Tent collapse
Floor brand fail at outer walls but interior load bearing wall or girder remains intact
External collapse
90deg angle collapse
Most dangerous as wall falls outward for distance at least equal to its height
Curtain fall collapse
part of wall comes straight down vertically and forms debris pile
Inward/Outward
Crack in middle of wall
Top falls in
bottom falls out
What is total collapse
Most severe form of structural failure
All floors have collapsed to the ground or basement
All walls collapsed into the floors
How could preplanning assist
Hazards size complexity contents processes occupancy and layout can all be recorded in ORD
Three greater London authorities with powers to deal with dangerous structures
The city corporation
Inner London borough councils
Outer London borough councils
If a building has become dangerous as a result of fire or if brigade informed of a dangerous building what should be done?
Send msg to London Operations Centre (LOC)
LOC will notify Dangerous Structures Engineer
Before arrival of dangerous structures engineer the brigade may have to safeguard by cordoning off any hazardous areas.
Collapsed structures will require investigation by
Police and HSE
Therefore preserve evidence
At collapsed structures there is a heightened risk of injury from
Restricted Access
Restricted vision
Underfoot conditions
Falling objects
Overhanging Hazards
Airborne particulate
Oxygen deficient atmosphere
Secondary collapse
Weight and position of casualties
Bulk and weight of debris
Explosive or flammable atmosphere
Poor lighting
Bio hazards
Exposed utilities
Asbestos
Sharp objects
Further acts of terrorism
Measures to consider at a collapsed structures incident are
Request dangerous structures engineer for early advice on structural integrity
Request USAR Advisor (UA) if not on PDA to assist in operational plan and for recommendation of additional It USAR resources
Request specialist teams from partner agencies
Early establishment of RVP
Dedicated USAR RVP if modules are deployed (UA can advise on site)
Position appliances away from weakened structures as vibration may cause further collapse
Appropriate PPE (BA, GTCPS)
Establishment of restricted zones
Don’t force doors or windows as they may be supporting a load
Personnel should keep close to walls when on weakened floors
Maintain liaison with and control of specialist contractors
Isolate utilities before rescue work proceeds
USAR capability includes which 5 modules
Module 1 Structural collapse
Module 2 Major Transport
Module 3 Breaching & Breaking
Module 4 Multi Purpose Vehicle (MPV)
Module 5 Timber
