Willis Tower - Revision history

Designing Buildings at 07:01, 11 November 2020

2020-11-11T07:01:25Z

← Older revision		Revision as of 07:01, 11 November 2020
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	* Vista Tower, Chicago.		* Vista Tower, Chicago.

−	[[Category:~~International~~]] [[Category:~~Projects_and_case_studies~~]] [[Category:~~DCN_Project_Knowledge~~]] [[Category:Design]]	+	[[Category:DCN_Commentary]] [[Category:DCN_Project_Knowledge]] [[Category:International]] [[Category:Projects_and_case_studies]] [[Category:Design]]

Editor at 09:16, 26 April 2017

2017-04-26T09:16:12Z

← Older revision		Revision as of 09:16, 26 April 2017
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	=== Related articles on Designing Buildings Wiki ===		=== Related articles on Designing Buildings Wiki ===

		+	* 150 North Riverside.
	* Building of the week series.		* Building of the week series.
	* Chrysler Building.		* Chrysler Building.
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	* Vista Tower, Chicago.		* Vista Tower, Chicago.

−	[[Category:International]] [[Category:Projects_and_case_studies]] [[Category:Design]]	+	[[Category:International]] [[Category:Projects_and_case_studies]] [[Category:DCN_Project_Knowledge]] [[Category:Design]]

Editor at 10:07, 5 April 2017

2017-04-05T10:07:05Z

← Older revision		Revision as of 10:07, 5 April 2017
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	Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.		Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.

−	The skyscraper is currently (2016) ~~the 11th tallest building in the world and~~ the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.	+	The skyscraper is currently (2016) the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.

	With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engineering systems made it very influential on subsequent skyscraper designs.		With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engineering systems made it very influential on subsequent skyscraper designs.

Editor at 15:10, 9 March 2017

2017-03-09T15:10:29Z

← Older revision		Revision as of 15:10, 9 March 2017
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	* Empire State Building.		* Empire State Building.
	* Fox Plaza, LA.		* Fox Plaza, LA.
		+	* Seagram Building.
	* Skyscraper.		* Skyscraper.
	* Structural principles.		* Structural principles.

Editor at 17:31, 16 November 2016

2016-11-16T17:31:21Z

← Older revision		Revision as of 17:31, 16 November 2016
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	Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.		Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.

−	The skyscraper is currently (2016) the ~~10th~~ tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.	+	The skyscraper is currently (2016) the 11th tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.

	With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engineering systems made it very influential on subsequent skyscraper designs.		With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engineering systems made it very influential on subsequent skyscraper designs.

Designing Buildings: Reverted edits by 5.151.1.0 (talk) to last revision by Designing Buildings

2016-11-07T06:27:29Z

Reverted edits by 5.151.1.0 (talk) to last revision by Designing Buildings

← Older revision		Revision as of 06:27, 7 November 2016
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	= Introduction =		= Introduction =

−	Willis Tower, popularly known by its former name Sears Tower, s a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.	+	Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.

	The skyscraper is currently (2016) the 10th tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.		The skyscraper is currently (2016) the 10th tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.

−	With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural ~~engin~~	+	With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engineering systems made it very influential on subsequent skyscraper designs.
		+
		+	The observation deck, Skydeck, is located on the 103rd floor and is a popular tourist attraction, with more than 1 million people visiting each year.
		+
		+	= Design and construction =

	[[File:Willistower2.jpg\|link=File:Willistower2.jpg]]		[[File:Willistower2.jpg\|link=File:Willistower2.jpg]]

5.151.1.0 at 00:16, 7 November 2016

2016-11-07T00:16:41Z

← Older revision		Revision as of 00:16, 7 November 2016
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	= Introduction =		= Introduction =

−	Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.	+	Willis Tower, popularly known by its former name Sears Tower, s a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.

	The skyscraper is currently (2016) the 10th tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.		The skyscraper is currently (2016) the 10th tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.

−	With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural ~~engineering systems made it very influential on subsequent skyscraper designs.~~	+	With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engin
−		+
−	~~The observation deck, Skydeck, is located on the 103rd floor and is a popular tourist attraction, with more than 1 million people visiting each year.~~	+
−		+
−	~~= Design and construction =~~	+

	[[File:Willistower2.jpg\|link=File:Willistower2.jpg]]		[[File:Willistower2.jpg\|link=File:Willistower2.jpg]]

Designing Buildings at 10:24, 26 October 2016

2016-10-26T10:24:21Z

← Older revision		Revision as of 10:24, 26 October 2016
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−	[[File:Willistower1.jpg\|~~428px~~]]	+	[[File:Willistower1.jpg\|link=File:Willistower1.jpg]]

	= Introduction =		= Introduction =
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	Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.		Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.

−	The skyscraper is currently the 10th tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.	+	The skyscraper is currently (2016) the 10th tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.

	With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engineering systems made it very influential on subsequent skyscraper designs.		With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engineering systems made it very influential on subsequent skyscraper designs.
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	= Design and construction =		= Design and construction =

−	[[File:Willistower2.jpg\|~~640px~~]]	+	[[File:Willistower2.jpg\|link=File:Willistower2.jpg]]

−	In 1969, Skidmore, Owings & Merrill (SOM) were hired by the retail giant Sears Roebuck and Company to design a new 3 million sq. ft office building ~~for them~~. The Chicago location was chosen for its logistical ease for employees, in close proximity to expressways and commuter rail lines.	+	In 1969, Skidmore, Owings & Merrill (SOM) were hired by the retail giant Sears Roebuck and Company to design a new 3 million sq. ft office building. The Chicago location was chosen for its logistical ease for employees, in close proximity to expressways and commuter rail lines.

−	The architect Bruce Graham and structural engineer Fazlur Khan ~~decided to design~~ the tower using Khan’s innovative new ~~method of~~ tube structural ~~engineering~~ which could alleviate some of the main ~~structural~~ issues faced by high-rise buildings.	+	The architect Bruce Graham and structural engineer Fazlur Khan designed the tower using Khan’s innovative new tube structural system which could alleviate some of the main issues faced by high-rise buildings.

−	They used ~~the~~ bundled tube system, grouping nine square tubes together, connected as a single unit. Each of these tubes was essentially a separate building, clustered in a 3x3 matrix to form a square base with sides measuring 69 m (225 ft). ~~The structure as a whole is strengthened as the tubes support one another. The structure of the tower is laid out as follows:~~	+	They used a bundled tube system, grouping nine square tubes together, connected as a single unit. Each of these tubes was essentially a separate building, clustered in a 3x3 matrix to form a square base with sides measuring 69 m (225 ft).

−	* All tubes rise to ~~equal height~~ to the 50th storey.	+	The structure of the tower is laid out as follows:
		+
		+	* All tubes rise to to the 50th storey.
	* Seven of the tubes continue while the northwest and southeast tubes finish.		* Seven of the tubes continue while the northwest and southeast tubes finish.
	* At the 66th storey, the northwest and southeast tubes finish.		* At the 66th storey, the northwest and southeast tubes finish.
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	Not only did this structural system provide greater strength and stability, since the tube height variations disrupt the wind force on the building, but it was also economically efficient in terms of cost per unit area.		Not only did this structural system provide greater strength and stability, since the tube height variations disrupt the wind force on the building, but it was also economically efficient in terms of cost per unit area.

−	Louvres are wrapped as black bands around the tower ~~at various storey heights~~, allowing ~~for~~ ventilation for ~~service~~ equipment, as well as ~~serving to obscure~~ the structure’s belt trusses.	+	Louvres are wrapped in black bands around the tower, allowing ventilation for building services equipment, as well as obscuring the structure’s belt trusses.

−	The building was completed in 1973 to a cost of around $150 million (equivalent to $800 m in 2016).	+	The building was completed in 1973 at a cost of around $150 million (equivalent to $800 m in 2016).

	= Post-construction =		= Post-construction =

−	[[File:Willis-towers-~~890353 640~~.jpg\|~~209px~~]]	+	[[File:Willis-towers-890353_640.jpg\|link=File:Willis-towers-890353_640.jpg]]

−	Although the tower was an engineering triumph, as a commercial entity it experienced more mixed fortunes. Sears were unable to fill the tower with as many office tenants as they had anticipated, which exacerbated their general decline over the 1970s as they lost market share. ~~As an~~ abundance of office space ~~in Chicago~~ was erected across the city during the 1980s, the Sears Tower stood half-vacant for many years.	+	Although the tower was an engineering triumph, as a commercial entity it experienced more mixed fortunes. Sears were unable to fill the tower with as many office tenants as they had anticipated, which exacerbated their general decline over the 1970s as they lost market share. An abundance of office space was erected across the city during the 1980s, and the Sears Tower stood half-vacant for many years.

−	In 1994, by which time the tower was one-third vacant, Sears sold it to AEW Capital Management, and ~~had~~ moved all of their commercial operations out of the building by 1995.	+	In 1994, by which time the tower was one-third vacant, Sears sold it to AEW Capital Management, and moved all of their commercial operations out of the building by 1995.

	In 1997, the Toronto-based TrizecHahn Corp paid $110 m to purchase the building. In 2003, they surrendered the building to the lender MetLife.		In 1997, the Toronto-based TrizecHahn Corp paid $110 m to purchase the building. In 2003, they surrendered the building to the lender MetLife.

−	In 2009, the London-based insurance company Willis Group Holdings took out a lease for more than 140,000 sq. ft of office space ~~across three floors of the building. As~~ part of their contract, ~~they had~~ the naming rights for 15 years.	+	In 2009, the London-based insurance company Willis Group Holdings took out a lease for more than 140,000 sq. ft of office space, and as part of their contract, purchased the naming rights for 15 years.

	In July of that year they changed the official name of the building to the Willis Tower. However, it is still commonly referred to as the Sears Tower and the renaming has been referred to by US media as one of the worst rebranding exercises in recent years.		In July of that year they changed the official name of the building to the Willis Tower. However, it is still commonly referred to as the Sears Tower and the renaming has been referred to by US media as one of the worst rebranding exercises in recent years.

−	Willis completed a major renovation of the Skydeck observation deck, which included installing retractable glass balconies~~. These extend approximately 1.2 m (4 ft) from the façade of the 103rd floor and can hold 4.5 tons of weight~~.	+	Willis completed a major renovation of the Skydeck observation deck, which included installing retractable glass balconies.

	In 2015, the Blackstone Group completed their purchase of the tower for an estimated $1.3 billion. At the time this was the highest price ever paid for an American property outside New York City. The owners are reported to be considering several plans for site developments.		In 2015, the Blackstone Group completed their purchase of the tower for an estimated $1.3 billion. At the time this was the highest price ever paid for an American property outside New York City. The owners are reported to be considering several plans for site developments.

Editor at 09:22, 26 October 2016

2016-10-26T09:22:31Z

← Older revision		Revision as of 09:22, 26 October 2016
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		+	[[File:Willistower1.jpg\|428px]]
		+
	= Introduction =		= Introduction =

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	= Design and construction =		= Design and construction =
		+
		+	[[File:Willistower2.jpg\|640px]]

	In 1969, Skidmore, Owings & Merrill (SOM) were hired by the retail giant Sears Roebuck and Company to design a new 3 million sq. ft office building for them. The Chicago location was chosen for its logistical ease for employees, in close proximity to expressways and commuter rail lines.		In 1969, Skidmore, Owings & Merrill (SOM) were hired by the retail giant Sears Roebuck and Company to design a new 3 million sq. ft office building for them. The Chicago location was chosen for its logistical ease for employees, in close proximity to expressways and commuter rail lines.
Line 30:		Line 34:

	= Post-construction =		= Post-construction =
		+
		+	[[File:Willis-towers-890353 640.jpg\|209px]]

	Although the tower was an engineering triumph, as a commercial entity it experienced more mixed fortunes. Sears were unable to fill the tower with as many office tenants as they had anticipated, which exacerbated their general decline over the 1970s as they lost market share. As an abundance of office space in Chicago was erected across the city during the 1980s, the Sears Tower stood half-vacant for many years.		Although the tower was an engineering triumph, as a commercial entity it experienced more mixed fortunes. Sears were unable to fill the tower with as many office tenants as they had anticipated, which exacerbated their general decline over the 1970s as they lost market share. As an abundance of office space in Chicago was erected across the city during the 1980s, the Sears Tower stood half-vacant for many years.

Editor: Created page with "= Introduction = Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in he..."

2016-10-26T09:20:58Z

Created page with "= Introduction = Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in he..."

New page

= Introduction =

Willis Tower, popularly known by its former name Sears Tower, is a commercial skyscraper located in Chicago, Illinois. At 108-storeys and 442 m (1,451 ft) in height, it was the tallest building in the world from its completion in 1973 until it was surpassed in 1998 by the Petronas Twin Towers.

The skyscraper is currently the 10th tallest building in the world and the second tallest in the United States, behind One World Trade Center in New York. However, the Willis Tower remains the tallest in the US in terms of roof and highest occupied floor.

With its black aluminium and bronze-tinted glass exterior, and multiple set-back levels, the tower has become symbolic of Chicago. Its use of pioneering structural engineering systems made it very influential on subsequent skyscraper designs.

The observation deck, Skydeck, is located on the 103rd floor and is a popular tourist attraction, with more than 1 million people visiting each year.

= Design and construction =

In 1969, Skidmore, Owings & Merrill (SOM) were hired by the retail giant Sears Roebuck and Company to design a new 3 million sq. ft office building for them. The Chicago location was chosen for its logistical ease for employees, in close proximity to expressways and commuter rail lines.

The architect Bruce Graham and structural engineer Fazlur Khan decided to design the tower using Khan’s innovative new method of tube structural engineering which could alleviate some of the main structural issues faced by high-rise buildings.

They used the bundled tube system, grouping nine square tubes together, connected as a single unit. Each of these tubes was essentially a separate building, clustered in a 3x3 matrix to form a square base with sides measuring 69 m (225 ft). The structure as a whole is strengthened as the tubes support one another. The structure of the tower is laid out as follows:

* All tubes rise to equal height to the 50th storey.
* Seven of the tubes continue while the northwest and southeast tubes finish.
* At the 66th storey, the northwest and southeast tubes finish.
* At the 90th storey, the north, east and south tubes finish.
* The remaining west and centre tubes continue to the 108th storey.

Not only did this structural system provide greater strength and stability, since the tube height variations disrupt the wind force on the building, but it was also economically efficient in terms of cost per unit area.

Louvres are wrapped as black bands around the tower at various storey heights, allowing for ventilation for service equipment, as well as serving to obscure the structure’s belt trusses.

The building was completed in 1973 to a cost of around $150 million (equivalent to $800 m in 2016).

= Post-construction =

Although the tower was an engineering triumph, as a commercial entity it experienced more mixed fortunes. Sears were unable to fill the tower with as many office tenants as they had anticipated, which exacerbated their general decline over the 1970s as they lost market share. As an abundance of office space in Chicago was erected across the city during the 1980s, the Sears Tower stood half-vacant for many years.

In 1994, by which time the tower was one-third vacant, Sears sold it to AEW Capital Management, and had moved all of their commercial operations out of the building by 1995.

In 1997, the Toronto-based TrizecHahn Corp paid $110 m to purchase the building. In 2003, they surrendered the building to the lender MetLife.

In 2009, the London-based insurance company Willis Group Holdings took out a lease for more than 140,000 sq. ft of office space across three floors of the building. As part of their contract, they had the naming rights for 15 years.

In July of that year they changed the official name of the building to the Willis Tower. However, it is still commonly referred to as the Sears Tower and the renaming has been referred to by US media as one of the worst rebranding exercises in recent years.

Willis completed a major renovation of the Skydeck observation deck, which included installing retractable glass balconies. These extend approximately 1.2 m (4 ft) from the façade of the 103rd floor and can hold 4.5 tons of weight.

In 2015, the Blackstone Group completed their purchase of the tower for an estimated $1.3 billion. At the time this was the highest price ever paid for an American property outside New York City. The owners are reported to be considering several plans for site developments.

As well as being a prominent feature on the Chicago skyline, and a popular tourist attraction, the tower has featured in several films and TV shows, such as ‘Ferris Bueller’s Day Off’, ‘I, Robot’, ‘Man of Steel’, and ‘Transformers: Dark of the Moon’.

= Find out more =

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

* Building of the week series.
* Chrysler Building.
* Empire State Building.
* Fox Plaza, LA.
* Skyscraper.
* Structural principles.
* Tallest buildings in the world.
* Tube structural system.
* Vista Tower, Chicago.

[[Category:International]] [[Category:Projects_and_case_studies]] [[Category:Design]]