Disproportionate collapse - Revision history

Designing Buildings at 08:47, 20 December 2020

2020-12-20T08:47:56Z

← Older revision		Revision as of 08:47, 20 December 2020
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	* [https://www.istructe.org/resources/guidance/disproportionate-collapse-2-volume-package/ Institution of Structural Engineers (IStruct E) publications.]		* [https://www.istructe.org/resources/guidance/disproportionate-collapse-2-volume-package/ Institution of Structural Engineers (IStruct E) publications.]

−	[[Category:~~Definitions~~]] [[Category:~~DCN_Definition~~]] [[Category:Construction_techniques]] [[Category:Design]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Definitions]] [[Category:Construction_techniques]] [[Category:Design]]

Editor at 19:50, 13 December 2019

2019-12-13T19:50:49Z

← Older revision		Revision as of 19:50, 13 December 2019
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	* Approved Document A.		* Approved Document A.
	* British post-war mass housing.		* British post-war mass housing.
		+	* Creep
	* De la Concorde overpass collapse.		* De la Concorde overpass collapse.
	* Defects in construction.		* Defects in construction.
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	* [https://www.istructe.org/resources/guidance/disproportionate-collapse-2-volume-package/ Institution of Structural Engineers (IStruct E) publications.]		* [https://www.istructe.org/resources/guidance/disproportionate-collapse-2-volume-package/ Institution of Structural Engineers (IStruct E) publications.]

−	[[Category:Definitions]] [[Category:Construction_techniques]] [[Category:Design]]	+	[[Category:Definitions]] [[Category:DCN_Definition]] [[Category:Construction_techniques]] [[Category:Design]]

Designing Buildings at 13:26, 27 November 2019

2019-11-27T13:26:54Z

← Older revision		Revision as of 13:26, 27 November 2019
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	= Pancake collapse =		= Pancake collapse =

−	In the US, the term ‘pancake collapse is sometimes used to describe the phenomenon of progressive collapse. The term was first used to describe a structural failure in the Bronx, New York, in August 1980, where a fire had weakened a structure to the extent that the floors fell successively in on one another, i.e they ‘pancaked’ down.	+	In the US, the term ‘pancake collapse' is sometimes used to describe the phenomenon of progressive collapse. The term was first used to describe a structural failure in the Bronx, New York, in August 1980, where a fire had weakened a structure to the extent that the floors fell successively in on one another, i.e they ‘pancaked’ down.

	A similar effect was seen at the destruction of the twin towers of the World Trade Center, New York in September 2001. The fire produced by the aircraft strikes resulted in the progressive failure of the floor system; although initiated by the attacks, this was later deduced to be the primary mode of structural failure in the steel frame buildings. A number of code changes were initiated as a result of the investigation, one of which was to increase by one hour the fire resistance of structural components.		A similar effect was seen at the destruction of the twin towers of the World Trade Center, New York in September 2001. The fire produced by the aircraft strikes resulted in the progressive failure of the floor system; although initiated by the attacks, this was later deduced to be the primary mode of structural failure in the steel frame buildings. A number of code changes were initiated as a result of the investigation, one of which was to increase by one hour the fire resistance of structural components.

Designing Buildings at 13:26, 27 November 2019

2019-11-27T13:26:27Z

← Older revision		Revision as of 13:26, 27 November 2019
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	= Building regulations =		= Building regulations =

−	~~Part A~~ of the ~~Approved Document (2004 edition, requirement A3) applies to all buildings (regardless of storeys or height) and~~ states:	+	Requirement A3 of the Building Regulations 2010 states:

	‘The building shall be constructed so that in the event of an accident the building will not suffer collapse to an extent disproportionate to the cause.’		‘The building shall be constructed so that in the event of an accident the building will not suffer collapse to an extent disproportionate to the cause.’

−	In other words, had Ronan Point been constructed in line with A3, the damage would have been ~~contained~~ to the floor where the explosion took place. Reducing a building’s ~~liability~~ to disproportionate collapse can be met by a range of constructions ~~given for guidance~~ in ~~Part A3~~.	+	In other words, had Ronan Point been constructed in line with requirement A3, the damage would have been restricted to the floor where the explosion took place. Reducing a building’s tendency to disproportionate collapse can be met by a range of constructions set out in Approved Document B of the Building Regulations.

	= Pancake collapse =		= Pancake collapse =

−	In the US, the term ‘pancake collapse is sometimes used to describe the phenomenon of progressive collapse. The term was first used to describe a structural failure in the Bronx, New York, in August 1980, where a fire had weakened ~~the~~ structure to the extent that the floors fell successively in on one another, i.e they ‘pancaked’ down.	+	In the US, the term ‘pancake collapse is sometimes used to describe the phenomenon of progressive collapse. The term was first used to describe a structural failure in the Bronx, New York, in August 1980, where a fire had weakened a structure to the extent that the floors fell successively in on one another, i.e they ‘pancaked’ down.

	A similar effect was seen at the destruction of the twin towers of the World Trade Center, New York in September 2001. The fire produced by the aircraft strikes resulted in the progressive failure of the floor system; although initiated by the attacks, this was later deduced to be the primary mode of structural failure in the steel frame buildings. A number of code changes were initiated as a result of the investigation, one of which was to increase by one hour the fire resistance of structural components.		A similar effect was seen at the destruction of the twin towers of the World Trade Center, New York in September 2001. The fire produced by the aircraft strikes resulted in the progressive failure of the floor system; although initiated by the attacks, this was later deduced to be the primary mode of structural failure in the steel frame buildings. A number of code changes were initiated as a result of the investigation, one of which was to increase by one hour the fire resistance of structural components.

−	~~To address the lack of confidence on the part of some designers in the application of the building regulations requirements on structural collapse, the~~ Institution of Structural Engineers (~~IStruct E~~) has published a two-volume guide to structural robustness and disproportionate collapse in buildings~~. The two parts are~~:	+	The Institution of Structural Engineers (IStructE) has published a two-volume guide to structural robustness and disproportionate collapse in buildings:

	* Practical guide to structural robustness and disproportionate collapse in buildings.		* Practical guide to structural robustness and disproportionate collapse in buildings.
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	* Prefab bungalows.		* Prefab bungalows.
	* Prefabrication.		* Prefabrication.
		+	* Ronan Point.
	* Structural failures.		* Structural failures.
	* The structural condition of Easiform cavity-walled dwellings (BR 130).		* The structural condition of Easiform cavity-walled dwellings (BR 130).

Editor at 18:03, 26 November 2019

2019-11-26T18:03:19Z

← Older revision		Revision as of 18:03, 26 November 2019
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	= Introduction =		= Introduction =

−	[[File:Jenga-~~stocksnap pixabay~~.jpg]]Disproportionate collapse (or progressive collapse) occurs in a building when the failure of one component leads to the progressive failure of a series of other components, often with catastrophic results.	+	[[File:Jenga-stocksnap_pixabay.jpg\|link=File:Jenga-stocksnap_pixabay.jpg]]Disproportionate collapse (or progressive collapse) occurs in a building when the failure of one component leads to the progressive failure of a series of other components, often with catastrophic results. The effect is very similar to that seen in a game of Jenga, pictured.

	= Ronan Point =		= Ronan Point =
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	A well-known example occurred in Newham, East London in May 1968 at a new 22-storey block of flats called Ronan Point. The reinforced concrete building featured prefabricated external wall panels. Unfortunately, a gas explosion resulted in the progressive collapse of an entire corner of the tower block, which killed four people and injured 17 other residents. The cause of the explosion was a resident striking a match to boil water which ignited the gas that was leaking from a joint in a newly-installed cooker.		A well-known example occurred in Newham, East London in May 1968 at a new 22-storey block of flats called Ronan Point. The reinforced concrete building featured prefabricated external wall panels. Unfortunately, a gas explosion resulted in the progressive collapse of an entire corner of the tower block, which killed four people and injured 17 other residents. The cause of the explosion was a resident striking a match to boil water which ignited the gas that was leaking from a joint in a newly-installed cooker.

−	[[File:~~Ronan Point~~.jpg]]	+	[[File:Ronan_Point.jpg\|link=File:Ronan_Point.jpg]]

	The explosion blew out the load-bearing flank walls, which had been supporting the four flats directly above, lifting the ceiling and floor slab. This resulted in a house-of-cards progressive collapse as the floors above became unsupported. For further details see Ronan point.		The explosion blew out the load-bearing flank walls, which had been supporting the four flats directly above, lifting the ceiling and floor slab. This resulted in a house-of-cards progressive collapse as the floors above became unsupported. For further details see Ronan point.

Editor: moved Progressive collapse to Disproportionate collapse

2019-11-26T17:41:51Z

moved Progressive collapse to Disproportionate collapse

← Older revision

Revision as of 17:41, 26 November 2019

Editor: Created page with "= Introduction = File:Jenga-stocksnap pixabay.jpgDisproportionate collapse (or progressive collapse) occurs in a building when the failure of one component leads to the prog..."

2019-11-26T17:41:19Z

Created page with "= Introduction = File:Jenga-stocksnap pixabay.jpgDisproportionate collapse (or progressive collapse) occurs in a building when the failure of one component leads to the prog..."

New page

= Introduction =

[[File:Jenga-stocksnap pixabay.jpg]]Disproportionate collapse (or progressive collapse) occurs in a building when the failure of one component leads to the progressive failure of a series of other components, often with catastrophic results.

= Ronan Point =

A well-known example occurred in Newham, East London in May 1968 at a new 22-storey block of flats called Ronan Point. The reinforced concrete building featured prefabricated external wall panels. Unfortunately, a gas explosion resulted in the progressive collapse of an entire corner of the tower block, which killed four people and injured 17 other residents. The cause of the explosion was a resident striking a match to boil water which ignited the gas that was leaking from a joint in a newly-installed cooker.

[[File:Ronan Point.jpg]]

The explosion blew out the load-bearing flank walls, which had been supporting the four flats directly above, lifting the ceiling and floor slab. This resulted in a house-of-cards progressive collapse as the floors above became unsupported. For further details see Ronan point.

Progressive collapse can be exploited deliberately as a demolition method to ensure a relatively quick and economic collapse if it is known the construction will respond appropriately.

= Building regulations =

Part A of the Approved Document (2004 edition, requirement A3) applies to all buildings (regardless of storeys or height) and states:

‘The building shall be constructed so that in the event of an accident the building will not suffer collapse to an extent disproportionate to the cause.’

In other words, had Ronan Point been constructed in line with A3, the damage would have been contained to the floor where the explosion took place. Reducing a building’s liability to disproportionate collapse can be met by a range of constructions given for guidance in Part A3.

= Pancake collapse =

In the US, the term ‘pancake collapse is sometimes used to describe the phenomenon of progressive collapse. The term was first used to describe a structural failure in the Bronx, New York, in August 1980, where a fire had weakened the structure to the extent that the floors fell successively in on one another, i.e they ‘pancaked’ down.

A similar effect was seen at the destruction of the twin towers of the World Trade Center, New York in September 2001. The fire produced by the aircraft strikes resulted in the progressive failure of the floor system; although initiated by the attacks, this was later deduced to be the primary mode of structural failure in the steel frame buildings. A number of code changes were initiated as a result of the investigation, one of which was to increase by one hour the fire resistance of structural components.

To address the lack of confidence on the part of some designers in the application of the building regulations requirements on structural collapse, the Institution of Structural Engineers (IStruct E) has published a two-volume guide to structural robustness and disproportionate collapse in buildings. The two parts are:

* Practical guide to structural robustness and disproportionate collapse in buildings.
* Manual for the systematic risk assessment of high-risk structures against disproportionate collapse.

= Related articles on Designing Buildings Wiki =

* Adam Curtis - The Great British Housing Disaster.
* Approved Document A.
* British post-war mass housing.
* De la Concorde overpass collapse.
* Defects in construction.
* Grenfell Tower fire.
* Modular buildings.
* Offsite manufacturing.
* Prefab bungalows.
* Prefabrication.
* Structural failures.
* The structural condition of Easiform cavity-walled dwellings (BR 130).

= External references =

* [https://www.istructe.org/resources/guidance/disproportionate-collapse-2-volume-package/ Institution of Structural Engineers (IStruct E) publications.]

[[Category:Definitions]] [[Category:Construction_techniques]] [[Category:Design]]