Tube structural system - Revision history

Designing Buildings at 07:55, 17 September 2020

2020-09-17T07:55:56Z

← Older revision		Revision as of 07:55, 17 September 2020
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	* The Constructor - [http://theconstructor.org/structural-engg/high-rise-structures/5/ High-rise structures]		* The Constructor - [http://theconstructor.org/structural-engg/high-rise-structures/5/ High-rise structures]

−	[[Category:Construction_techniques]] [[Category:Design]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]] [[Category:Design]]

Editor at 14:42, 21 March 2018

2018-03-21T14:42:43Z

← Older revision		Revision as of 14:42, 21 March 2018
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	* Concrete-steel composite structures.		* Concrete-steel composite structures.
	* Shear wall.		* Shear wall.
		+	* Skeleton frame.
	* Skyscraper.		* Skyscraper.
	* Structural engineer.		* Structural engineer.

Editor at 15:10, 17 July 2017

2017-07-17T15:10:50Z

← Older revision		Revision as of 15:10, 17 July 2017
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	* Concept structural design of buildings.		* Concept structural design of buildings.
	* Concrete-steel composite structures.		* Concrete-steel composite structures.
		+	* Shear wall.
	* Skyscraper.		* Skyscraper.
	* Structural engineer.		* Structural engineer.

Editor at 09:23, 26 October 2016

2016-10-26T09:23:40Z

← Older revision		Revision as of 09:23, 26 October 2016
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	* The development of structural membranes.		* The development of structural membranes.
	* Types of structural load.		* Types of structural load.
		+	* Willis Tower.

	=== External resources ===		=== External resources ===

Designing Buildings at 05:45, 25 October 2016

2016-10-25T05:45:50Z

← Older revision		Revision as of 05:45, 25 October 2016
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	= Introduction =		= Introduction =

−	The tube is a structural engineering system that is used in high-rise ~~office~~, ~~apartment and mixed-use buildings. It enables buildings~~ to resist lateral loads from wind ~~and~~ seismic pressures, and so on~~, by acting~~ like a hollow cylinder, cantilevered perpendicular to the ground.	+	The tube is a structural engineering system that is used in high-rise buildings, enabling them to resist lateral loads from wind, seismic pressures and so on. It acts like a hollow cylinder, cantilevered perpendicular to the ground.

	The system was developed in the 1960s by the engineer Fazlur Rahman Khan, and has been used to construct most high-rise buildings since then.		The system was developed in the 1960s by the engineer Fazlur Rahman Khan, and has been used to construct most high-rise buildings since then.
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	The tube system can be constructed using concrete, steel or a composite of both. In its simplest form, closely-spaced columns are tied together with deep spandrel beams through moment connections as part of the external perimeter of the building. The rigid frame that this assembly of columns and beams forms results in a dense and strong structural ‘tube’ around the exterior.		The tube system can be constructed using concrete, steel or a composite of both. In its simplest form, closely-spaced columns are tied together with deep spandrel beams through moment connections as part of the external perimeter of the building. The rigid frame that this assembly of columns and beams forms results in a dense and strong structural ‘tube’ around the exterior.

−	Since lateral loads can be resisted by ~~the~~ stiff exterior framing, interior columns can be located at the core and are fewer in number. The interior can be simply framed for gravity loads and floor space is left free from columns.	+	Since lateral loads can be resisted by this stiff exterior framing, interior columns can be located at the core and are fewer in number. The interior can be simply framed for gravity loads and floor space is left free from columns.

	The first building designed by Khan using a tube frame was the DeWitt-Chestnut building, Chicago, in 1963. The first skyscraper to use the system was Chicago’s Willis Tower.		The first building designed by Khan using a tube frame was the DeWitt-Chestnut building, Chicago, in 1963. The first skyscraper to use the system was Chicago’s Willis Tower.
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	= Types of system =		= Types of system =

−	~~The basic tube system has been adapted to suit different requirements of structures.~~ The most common of ~~these~~ variations are as follows:	+	The most common of variations are as follows:

	== Framed tube ==		== Framed tube ==

−	This is the simplest form of the tube system and can be used on a variety of floor plan shapes, including square, rectangular, circular and freeform. This type is reasonably efficient from 38-300 m (125-1,000 ft) in height. ~~Framed tube~~ was the initial system type developed by Khan.	+	This is the simplest form of the tube system and can be used on a variety of floor plan shapes, including square, rectangular, circular and freeform. This type is reasonably efficient from 38-300 m (125-1,000 ft) in height. It was the initial system type developed by Khan.

	Khan defined a framed tube structure as "a three dimensional space structure composed of three, four, or possibly more frames, braced frames, or shear walls, joined at or near their edges to form a vertical tube-like structural system capable of resisting lateral forces in any direction by cantilevering from the foundation."		Khan defined a framed tube structure as "a three dimensional space structure composed of three, four, or possibly more frames, braced frames, or shear walls, joined at or near their edges to form a vertical tube-like structural system capable of resisting lateral forces in any direction by cantilevering from the foundation."
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	== Trussed tube ==		== Trussed tube ==

−	Trussed (also known as braced) tube systems are similar to the framed tube but have fewer exterior columns space further apart. To compensate for the fewer columns, steel ~~bracings~~ or concrete shear walls are introduced to tie the columns together.	+	Trussed (also known as braced) tube systems are similar to the framed tube but have fewer exterior columns space further apart. To compensate for the fewer columns, steel bracing or concrete shear walls are introduced to tie the columns together.

	By interconnecting all the exterior columns, it forms a rigid box which is capable of resisting lateral shears by axial in its members rather than through flexure (bending or curving).		By interconnecting all the exterior columns, it forms a rigid box which is capable of resisting lateral shears by axial in its members rather than through flexure (bending or curving).

−	By having relatively broad column spacing, ~~there~~ is ~~the possibility of having~~ lots of clear ~~spaces~~ for windows.	+	By having relatively broad column spacing, it is possible to have lots of clear space for windows.

	The diagonals that are introduced on each façade should intersect at the same point on the corner column. These diagonals interact with the perpendicular face trusses to make the structure ‘tubular’ and equalise the gravity loads of the exterior columns.		The diagonals that are introduced on each façade should intersect at the same point on the corner column. These diagonals interact with the perpendicular face trusses to make the structure ‘tubular’ and equalise the gravity loads of the exterior columns.
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	== Hybrid system ==		== Hybrid system ==

−	A hybrid system is often used where the building design has a slenderness that a single system cannot provide adequate strength or stiffness ~~for~~. It combines two or more basic structural forms, either by direct combination or by adopting different forms in different parts of the structure. As high-rise building designs ~~get~~ more complex, hybrid systems are an increasingly common ~~solution~~.	+	A hybrid system is often used where the building design has a slenderness such that a single system cannot provide adequate strength or stiffness. It combines two or more basic structural forms, either by direct combination or by adopting different forms in different parts of the structure. As high-rise building designs become more complex, hybrid systems are increasingly common.

	= Find out more =		= Find out more =

Editor at 14:30, 24 October 2016

2016-10-24T14:30:35Z

← Older revision		Revision as of 14:30, 24 October 2016
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	* Braced frame.		* Braced frame.
	* Concept structural design of buildings.		* Concept structural design of buildings.
−	* Concrete-steel composite ~~structure~~.	+	* Concrete-steel composite structures.
	* Skyscraper.		* Skyscraper.
	* Structural engineer.		* Structural engineer.

Editor: Created page with "= Introduction = The tube is a structural engineering system that is used in high-rise office, apartment and mixed-use buildings. It enables buildings to resist lateral loads fr..."

2016-10-24T14:29:59Z

Created page with "= Introduction = The tube is a structural engineering system that is used in high-rise office, apartment and mixed-use buildings. It enables buildings to resist lateral loads fr..."

New page

= Introduction =

The tube is a structural engineering system that is used in high-rise office, apartment and mixed-use buildings. It enables buildings to resist lateral loads from wind and seismic pressures, and so on, by acting like a hollow cylinder, cantilevered perpendicular to the ground.

The system was developed in the 1960s by the engineer Fazlur Rahman Khan, and has been used to construct most high-rise buildings since then.

The tube system can be constructed using concrete, steel or a composite of both. In its simplest form, closely-spaced columns are tied together with deep spandrel beams through moment connections as part of the external perimeter of the building. The rigid frame that this assembly of columns and beams forms results in a dense and strong structural ‘tube’ around the exterior.

Since lateral loads can be resisted by the stiff exterior framing, interior columns can be located at the core and are fewer in number. The interior can be simply framed for gravity loads and floor space is left free from columns.

The first building designed by Khan using a tube frame was the DeWitt-Chestnut building, Chicago, in 1963. The first skyscraper to use the system was Chicago’s Willis Tower.

= Types of system =

The basic tube system has been adapted to suit different requirements of structures. The most common of these variations are as follows:

== Framed tube ==

This is the simplest form of the tube system and can be used on a variety of floor plan shapes, including square, rectangular, circular and freeform. This type is reasonably efficient from 38-300 m (125-1,000 ft) in height. Framed tube was the initial system type developed by Khan.

Khan defined a framed tube structure as "a three dimensional space structure composed of three, four, or possibly more frames, braced frames, or shear walls, joined at or near their edges to form a vertical tube-like structural system capable of resisting lateral forces in any direction by cantilevering from the foundation."

== Trussed tube ==

Trussed (also known as braced) tube systems are similar to the framed tube but have fewer exterior columns space further apart. To compensate for the fewer columns, steel bracings or concrete shear walls are introduced to tie the columns together.

By interconnecting all the exterior columns, it forms a rigid box which is capable of resisting lateral shears by axial in its members rather than through flexure (bending or curving).

By having relatively broad column spacing, there is the possibility of having lots of clear spaces for windows.

The diagonals that are introduced on each façade should intersect at the same point on the corner column. These diagonals interact with the perpendicular face trusses to make the structure ‘tubular’ and equalise the gravity loads of the exterior columns.

== Tube-in-tube ==

This system is also known as ‘hull and core’ and consists of a core tube inside the structure which holds services such as utilities and lifts, as well as the usual tube system on the exterior which takes the majority of the gravity and lateral loads.

The inner and outer tubes interact horizontally as the shear and flexural components of a wall-frame structure. They have the advantage of increased lateral stiffness.

== Bundled tube ==

The bundled tube system involves, instead of one tube, several individual tubes interconnected to form a multi-cell tube. Together they work to resist the lateral loads and overturning moments. When the tubes fall within the building envelope, interior columns are positioned along their perimeters.

Not only is this system economically efficient but it also allows for more versatile building designs, adopting interesting shapes and bundled in dynamic groupings rather than being simply box-like towers.

The first type of building to use this system was the Willis Tower in Chicago.

== Hybrid system ==

A hybrid system is often used where the building design has a slenderness that a single system cannot provide adequate strength or stiffness for. It combines two or more basic structural forms, either by direct combination or by adopting different forms in different parts of the structure. As high-rise building designs get more complex, hybrid systems are an increasingly common solution.

= Find out more =

=== Related articles on Designing Buildings Wiki ===

* Braced frame.
* Concept structural design of buildings.
* Concrete-steel composite structure.
* Skyscraper.
* Structural engineer.
* Structural principles.
* Structural steel.
* The development of structural membranes.
* Types of structural load.

=== External resources ===

* The Constructor - [http://theconstructor.org/structural-engg/high-rise-structures/5/ High-rise structures]

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