PN 302 - Collapsed Structures (not finished)

Question 1

PN 302 - Collapsed Structures

List the causes of NATURAL collapse.

(5)

Answer 1

SHELF

• Subsidence.
• Hurricane.
• Earthquake.
• Lightning.
• Flooding.

Question 2

PN 302 - Collapsed Structures

List the causes of NATURAL collapse.

(5)

Answer 2

SHELF

• Subsidence.
• Hurricane.
• Earthquake.
• Lightning.
• Flooding.

Question 3

PN 302 - Collapsed Structures

List the causes of HUMAN collapse.

(5)

Answer 3

• Premises under renovation.
• Accidental impact.
• Arson.
• Terrorist induced (aeroplane impact, vehicle impact. etc.).
• Accidental gas explosion.

On many occasions the collapse will occur without warning, leaving casualties little or no time to escape. This can result in a number of casualties being trapped under large amounts of unstable debris.

Question 4

PN 302 - Collapsed Structures

When considering structural damage, buildings may be divided into two classes.

What are they?

+

Explain the construction methods and where they are found

+

Explain how they behave in relation to collapse.

Answer 4

• Framed buildings:

A skeleton/frame of steel/reinforced concrete supports the structural load (floors, roof).

Found in modern public buildings, e.g. office blocks and hospitals

Framed buildings have a greater resistance to collapse and, in general, failures that occur are more localised.

• Unframed buildings:

Walls carry the structural loads. Walls support floors and roofs, and typical brick and joist structure is usual.

Traditional form of construction in UK and many countries abroad.

If the load bearing walls fail along with columns or floor beams, the result is an extensive collapse, with a large area of debris.

Question 5

PN 302 - Collapsed Structures

Collapse types can be categorised into 3 types. Name them

Answer 5

• Internal
• External
• Total collapse

Question 6

PN 302 - Collapsed Structures

List the different types of INTERNAL collapse

Answer 6

• Pancake collapse
• Lean-to collapse
• V collapse
• Tent collapse

*

Question 7

PN 302 - Collapsed Structures

What is the most dangerous form of external collapse and why?

Answer 7

9Oo angle collapse is the most dangerous form of external collapse as the wall falls outwards for a distance at least equal to its height

Question 8

PN 302 - Collapsed Structures

List the 3 different types of external collapse.

Answer 8

• 90o angle collapse
• Curtain fall collapse
• Inward/outward collapse

Question 9

PN 302 - Collapsed Structures

What is the most severe form of structural failure?

Answer 9

Total collapse

Where all the floors have collapsed to the ground or basement level and all walls have collapsed onto the floors.

Question 10

PN 302 - Collapsed Structures

The USAR capability consists of 5 modules plus prime movers as follows

Answer 10

• Module 1 – Structural collapse
• Module 2 - Major transport
• Module 3 – Breaching and Breaking
• Module 4 – Multi purpose vehicle (MPV)
• Module 5 – Timber

Question 11

PN 302 - Collapsed Structures

List the six stages of rescue

Answer 11

R - Reconnaissance and survey.

E - Elimination of utilities

P - Primary surface search and rescue

E - Exploration of voids and spaces

A - Access by selected debris removal

T - Terminate by general debris removal

Question 12

PN 302 - Collapsed Structures

How should offers of assistance from Non-Government Organisations (NGOs) should be dealt with?

Answer 12

Referred to the Officer of the day (OOD), via LOC, who will refer the offer to the duty Assistant Commissioner for consideration.