10 Tallest structures in world - Burj Dubai surpasses all
The CN Tower in Toronto, Ontario was the world's tallest freestanding structure on land from 1975 until Burj Dubai surpassed it in 2007. Rising 553.33 meters (1,815 ft), it is currently the world's tallest completed freestanding structure on land.
The tallest man made structure is Burj Dubai, a skyscraper under construction in Dubai that reached 818 m (2,684 ft) in height on 17 January 2009. By 7 April 2008 it had been built higher than the KVLY-TV mast in North Dakota, USA, which is still the tallest completed structure at 628.8 meters (2,063 ft). In September it officially surpassed Poland's 646.38 m (2,121 ft) Warsaw radio mast, which stood from 1974 to 1991, to become the tallest structure ever built. Guyed lattice towers such as these masts had held the world height record since 1954.
The CN Tower in Toronto, Ontario, Canada, standing at 553.3 m (1,815 ft), is the world's tallest completed freestanding structure on land. Opened in 1976, it was surpassed in height by the rising Burj Dubai on September 12, 2007. It has the world's second highest public observation deck at 446.5 meters (1,465 ft).
The Petronius Platform stands 610 meters (2,001 ft) off the sea floor leading some, including Guinness World Records 2007, to claim it as the tallest freestanding structure in the world. However, it is debated whether underwater height should be discounted in the same manner as height below grade is ignored on buildings. The Troll A platform is 472 meters (1,549 ft), without any part of that height being supported by wires. The tension-leg type of oil platform has even greater below-water heights with several examples more than 1,000 meters (3,300 ft) deep. However, these platforms are not considered constant structures as the vast majority of their height is made up of the length of the tendons attaching the floating platforms to the sea floor. Despite this, Guiness World Records 2009 listed the Ursa tension leg platform as the tallest structure in the world with a total height of 1,306 meters (4,285 feet).
Taipei 101 in Taipei, Taiwan is currently the world's tallest inhabited building in only one of the four main categories that are commonly measured: at 509.2 meters (1,671 ft) as measured to its architectural height (spire). Its roof height 449.2 meters (1,474 ft) and highest occupied floor 439.2 meters (1,441 ft) have recently been overtaken by the Shanghai World Financial Center (roof height 487 meters (1,598 ft); highest occupied floor 474 meters (1,555 ft)). Willis Tower (formerly Sears Tower) is highest in the final category: the greatest height to top of antenna of any building in the world at 527.3 meters (1,730 ft).
On its completion, projected for late 2009, Burj Dubai will break the height record in all four categories for completed buildings by a wide margin. The Shanghai World Financial Center has the world's highest roof, highest occupied floor, and the world's highest public observation deck at 474.2 meters (1,556 ft). It will retain the latter record after the completion of Burj Dubai, as Burj Dubai's observation deck will be at 442 meters (1,450 ft).
Top 10 tallest structures in the world
| Rank | Structure | City | Meters | Feet | Built |
| 1 | Burj Dubai | Dubai | 818 | 2,684[2] | 2009 |
| 2 | KVLY-TV mast | Blanchard | 628.8 | 2063 | 1963 |
| 3 | Guangzhou TV Tower | Guangzhou | 610 | 2001 | 2009 |
| 4 | CN Tower | Toronto | 553.3 | 1815 | 1976 |
| 5 | Willis Tower | Chicago | 527.3 | 1730 | 1973 |
| 6 | Taipei 101 | Taipei | 509.2 | 1671 | 2004 |
| 7 | Shanghai World Fin Cent | Shanghai | 492 | 1614 | 2008 |
| 8 | BREN Tower | Nevada Site | 462 | 1516 | 1962 |
| 9 | Petronas Twin Towers | Kuala Lumpur | 452 | 1482 | 1998 |
| 10 | GRES-2 Power Station | Ekibastusz | 419.7 | 1377 | 1987 |
s1. Burj Dubai
Burj Dubai, a supertall skyscraper under construction in Dubai, United Arab Emirates, is the tallest man-made structure ever built, at 818 meters (2,684 ft). Construction began on 21 September 2004, and the tower is expected to be completed and ready for occupancy on 4 January 2010.
The building is part of the 2 square kilometres flagship development called "Downtown Burj Dubai" at the "First Interchange" along Sheikh Zayed Road, near Dubai's main business district. The tower's architect is Adrian Smith, who worked with Skidmore, Owings and Merrill (SOM) until 2006. The Chicago based architecture and engineering firm SOM is in charge of the project. The primary builders are Samsung Engineering & Construction and Besix along with Arabtec. Turner Construction Company was chosen as the construction manager.
The total budget for the Burj Dubai project is about USD 4.1 billion, and for the entire new "Downtown Dubai", USD 20 billion.
Timeline
* 21 September 2004: Emaar contractors begin construction.
* February 2007: Surpasses the Sears Tower (since renamed the Willis Tower) as the building with the most floors.
* 13 May 2007: Sets record for vertical concrete pumping on any building at 452 m (1,483 ft), surpassing the 449.2 m (1,474 ft) to which concrete was pumped during the construction of Taipei 101.
* 21 July 2007: Surpasses Taipei 101, whose height of 509.2 meters71 ft) made it the world's tallest building.
* 12 August 2007: Surpasses the Sears Tower (Willis Tower) antenna, which stands 527.3 meters (1,730 ft).
* 12 September 2007: At 555.3 m (1,822 ft), becomes the world's tallest freestanding structure, surpassing the CN Tower in Toronto.
* 7 April 2008: At 629 m (2,064 ft), surpasses the KVLY-TV Mast to become the tallest man-made structure.
* 17 June 2008: Emaar announces that Burj Dubai's height is over 636 m (2,087 ft) and that its final height will not be given until it is completed in September 2009.
* 1 September 2008: Height tops 688 m (2,257 ft), making it the tallest man-made structure ever built, surpassing the previous record-holder, the Warsaw Radio Mast in Konstantynów , Poland.
* 17 January 2009: Topped out at 818 meter (2,684 ft).
* 1 October 2009: Emaar announces that the exterior of the building is completed.
2. KVLY-TV mast
The KVLY-TV mast (formerly the KTHI-TV mast) is a 2,063 ft (629 m) tall television-transmitting mast in Blanchard, Traill County, North Dakota, United States, used by Fargo station KVLY channel 11. It's considered the third tallest structure ever built, after Burj Dubai and the Warsaw radio mast (which collapsed in 1991).
Type TV transmission tower
Location Blanchard, Traill County, North Dakota
Owner Hoak Media
Coordinates 47°20′32″N 97°17′21″W / 47.34222°N 97.28917°W / 47.34222; -97.28917Coordinates: 47°20′32″N 97°17′21″W / 47.34222°N 97.28917°W / 47.34222; -97.28917
Construction
Completed August 13, 1963
Height 628.8 m (2,063 ft)
Main contractor Kline Iron and Steel
Design team
Architect Hamilton Directors
The tower is located three miles west of Blanchard, North Dakota, halfway between Fargo and Grand Forks. It became the tallest artificial structure upon the completion of its construction on 13 August 1963. The mast was surpassed in height by 57 ft (17 m) in 1974 by the Warszawa radio mast near Konstantynów, Poland, which collapsed on 8 August 1991, making the KVLY-TV mast again the tallest structure on land.
The still-under-construction Burj Dubai in Dubai, United Arab Emirates, planned for completion in December 2009, has surpassed the mast as the tallest land structure. As of 17 January 2009, Burj Dubai was reported to have reached a height of 818 metres (2,684 ft). However, the Council on Tall Buildings and Urban Habitat will not recognize the Burj Dubai figures as official until that building is complete[citation needed].
The tower was built by Hamilton Electric Company York, South Carolina and Kline Iron and Steel, and took thirty days to complete, at a cost of US$500,000.
Owned by Hoak Media of Dallas, Texas, the tower broadcasts at 316 kW for television station KVLY (channel 11, an NBC affiliate) which is based in Fargo. The tower provides a broadcast area of roughly 30,000 sq mi (78,000 km2) which is a radius of about 97 miles (156 km).
Its height above mean sea level is 3,038 ft (926 m). Some time after its completion, the FCC and FAA imposed a policy that states, "Although there is no absolute height limit for antenna towers, both agencies have established a rebuttable presumption against structures over 2,000 feet above ground level." The FCC and FAA may approve a taller structure in "exceptional cases."
The call letters of the television station for which it was built were originally KTHI, the "HI" referring to the height of the mast. The top is reachable by elevator or ladder.
3. Guangzhou TV & Sightseeing Tower
Guangzhou TV & Sightseeing Tower is a tower currently under construction near Chigang Pagoda, Haizhu District, Guangzhou, China. It is due to be completed at the end of 2009, in order to be fully operational for the 2010 Asian Games.
Location Guangzhou, China
Coordinates 23°06′23.3″N 113°19′28.5″E / 23.106472°N 113.324583°E / 23.106472; 113.324583Coordinates: 23°06′23.3″N 113°19′28.5″E / 23.106472°N 113.324583°E / 23.106472; 113.324583
Status Second Tallest Metal Tower
Groundbreaking November 2005
Estimated completion 2009
Use observation, telecommunications
Height
Antenna/Spire 610 m (2,001.3 ft)
Roof 454 m (1,489.5 ft)
Technical details
Floor count 37 (excl. 2 below ground)
Floor area 114,054 m2 (1,227,700 sq ft)
Companies
Architect Mark Hemel, Barbara Kuit; IBA
Structural Engineer Arup
The TV & Sightseeing Tower is the first significant XL project designed by the Dutch architects Mark Hemel and Barbara Kuit. Their company Information Based Architecture, based in Amsterdam is at the forefront of architectural design creating innovative and highly artistic architecture using the state of the Art technologies and materials. The practice collaborated with Arup, the global design and business consulting firm headquartered in London, UK. The design was awarded first prize in a competition that was also joined by, among others, Coop Himmelblau, Richard Rogers Partnership, Cannon and KPF. In 2004 the IBA - Arup team in Amsterdam developed the concept design. In later stages IBA cooperated mainly with the local Chinese offices of Arup and a Local Design Institute. The tower is due to be completed in the beginning of 2010.
The form, volume and hyperboloid structure are generated by two ellipses, one at foundation level and the other at an imaginary horizontal plane just above 450 metres. The tightening caused by the rotation between the two ellipses forms the characterizing ‘waist-line 'of the tower, and a densification of material. This means that the lattice structure, which at the bottom of the tower is porous and spacious, becomes denser at waist level. The waist itself is tightened, like a twisted rope; further up the tower the lattice opens again, accentuated here by the tapering of the structural column-tubes.
The waist of the tower contains a 180m long open-air skywalk where visitors can physically climb the tower. There are outdoor gardens set within the structure and at the top at +450m a large open-air observation deck.
The interior of the tower will be subdivided into programmatic zones with various functions including: TV and radio transmission facilities, observatory decks, revolving restaurants, computer gaming, restaurants, exhibition spaces, conference rooms, shops and 4D cinemas.
A deck at the base of the tower hides the tower's functional workings. All infrastructural connections - metro and bus stations, and a pedestrian link to the northern embankment of the river - are met underground. This level supports other facilities as well, including a museum, a food court, extensive commercial space, a 600-vehicle parking area for cars and tourist coaches. The entrance operates on two levels, one a continuation of the landscape above ground, the other connected to the mass-transit and underground-parking facilities. Slow-speed panoramic and enclosed high-speed double-decker lifts serve both entrance levels.
The intermediate zone, from +80m up to +170m, consist of facilities including a 4D cinema, a play-hall area, restaurants, coffee shops and outdoor gardens with teahouses. An open-air staircase, the Skywalk, starts at the height of +170 metres and spirals almost 200 metres higher, all the way through the waist.
The top zone of the tower begins above the stairway, housing various technical functions as well as a two-storey rotating restaurant, a damper and the upper observation levels. From the upper observation levels it is possible to ascend even higher, via a further set of the stairs, to a terraced observation square rising above the tower's top ring.
4. CN Tower
The CN Tower was the world's tallest free-standing tower from 1975 to 2008.
Location Toronto, Ontario, Canada
Coordinates 43°38′33″N 79°23′14″W / 43.6426°N 79.3871°W / 43.6426; -79.3871Coordinates: 43°38′33″N 79°23′14″W / 43.6426°N 79.3871°W / 43.6426; -79.3871
Status Complete
Constructed 1973-1976
Use observation, telecommunications, attraction
Height
Antenna/Spire 553.33 m (1,815.4 ft)
Roof 457.2 m (1,500.0 ft)
Top floor 446.5 m (1,464.9 ft)
Technical details
Floor count 147 (equivalent)
Elevator count 6
Companies
Architect John Andrews Architects in association with WZMH Architects
The CN Tower, is in downtown Toronto, Ontario, Canada, is a tower. It beated the height of the Ostankino Tower while still under construction in 1975, becoming the tallest free-standing structure on land in the world. On September 26, 2007, after holding the record for 39 years, the CN Tower was surpassed in height by the still-under-construction Burj Dubai. It remains the tallest structure in the Americas, the signature icon of Toronto's skyline, and a symbol of Canada, attracting more than three million international visitors annually.[
CN was called Canadian National, the railway company that built the tower. Following the railway's decision to divest non-core freight railway assets, prior to the company's privatization in 1995 it transferred the tower to the Canada Lands Company, a federal Crown corporation responsible for real estate development. Since local residents wished to retain the name CN Tower, the abbreviation is now said to expand to Canada's National Tower rather than the original Canadian National Tower; however, neither of these names are commonly used.[
In 1995, the CN Tower was declared one of the modern Seven Wonders of the World by the American Society of Civil Engineers. It also belongs to the World Federation of Great Towers.
The idea of the CN Tower originated from the 1968 the Railway company]] wanted to build a large TV and talking station platform to serve the Toronto area, as well as show the strength of Canadian industry and CN in at the same. These plans evolved over the next few years, and the project became known in 1972. The tower would have been part of Metro Centre (see CityPlace), a large development south of Front Street on the Railway Lands, a large railway switching yard that was being made redundant by newer yards outside the city. Key project team members were NCK Engineering as structural engineer; John Andrews Architects; Webb, Zerafa, Menkes, Housden Architects; Foundation Building Construction; and Canron (Eastern Structural Division).
At the time, Toronto was a large town, and the late 1960s and early 1970s had seen the start of numerous large skyscrapers in the downtown core, most notably First Canadian Place. This made broadcasting into the downtown area very difficult due to reflections off the buildings. The only answer would be to raise the antennas above the buildings, demanding a tower over 100 metres (328 ft) tall. Additionally, at the time, most data communications took place over point-to-point microwave links, whose dish antenna covered the roofs of large buildings. As each new skyscraper was added to the town, former line-of-sight links were no longer working. CN intended to rent "hub" space for microwave links, visible from almost any building in the Toronto area. The CN Tower can be seen from at least as far away as Kennedy Street in Aurora, Ontario, about 40 kilometres (25 mi) to the north, and from several points on the south shore of Lake Ontario, 48 kilometres (30 mi) to the south in New York state in the United States.[original research?]
The original plan for the tower envisioned a tripod consisting of three independent cylindrical "pillars" linked at various heights by structural bridges. Had it been built, this design would have been considerably shorter, with the metal antenna located roughly where the concrete section between the main level and the Sky Pod lies today. As the design effort continued, it evolved into the current design with a single continuous hexagonal core to the Sky Pod, with three support legs blended into the hexagon below the main level, forming a large Y-shape structure at the ground level.
The idea for the main level in its current form evolved around this time, but the Sky Pod was not part of the plans until some time later. One engineer in particular felt that visitors would feel the higher observation deck would be worth paying extra for, and the costs in terms of construction were not prohibitive. It was also some time around this point that it was realized that the tower could become the world's tallest structure, and plans were changed to incorporate subtle modifications throughout the structure to this end.
On June 26, 1986, the ten-year calabration of the tower's opening, high-rise firefighting and rescue advocate Dan Goodwin, in a sponsored publicity event, used his hands and feet to climb the tower, a feat he performed twice on the same day. Following both ascents, he used multiple rappels to descend to the ground.
5. Willis Tower
Willis Tower was the world's tallest building from 1974 to 1998.
Preceded by World Trade Center
Surpassed by Petronas Twin Towers
Location 233 S. Wacker Drive
Chicago, Illinois 60606
United States
Status Complete
Constructed 1970-1973
Use Office, observation, communication
Height
Antenna/Spire 1,730 feet (527 m)
Roof 1,451 ft (442 m)[1]
Technical details
Floor count 108[1]
Floor area 4.56 million sq ft. (3.81 million sq ft. rentable)
418,064 m² (353,961 m² rentable)[2]
Elevator count 104, with 16 double-decker elevators, made by Westinghouse, modernized by Schindler Group
Companies
Architect Skidmore, Owings and Merrill
Willis Tower, formerly named Sears Tower, is a 108-story 1,450 feet (442 m) skyscraper in Chicago, Illinois. At the time of its completion in 1973 it was the tallest building in the world, surpassing the World Trade Center towers in New York. Currently, Willis Tower is the tallest building in the United States and the fifth-tallest freestanding structure in the world.
Although Sears' naming rights expired in 2003, the building continued to be called Sears Tower for several years. However, in March 2009 London-based insurance broker Willis Group Holdings, Ltd., agreed to lease a portion of the building and obtained the building's naming rights as part of the agreement. On July 16, 2009, at 10:00 am Central Time, the building was officially renamed Willis Tower.
In 1969, Sears, Roebuck & Co. was the largest retailer in the world, with approximately 350,000 employees. Sears executives decided to consolidate the thousands of employees in offices distributed throughout the Chicago area into one building on the western edge of Chicago's Loop. With immediate space demands of 3 million square feet (279,000 m²), and predictions and plans for future growth necessitating even more space, Sears commissioned architects Skidmore, Owings and Merrill to produce a structure that would be one of the largest office buildings in the world. Their team of architect Bruce Graham and structural engineer Fazlur Khan designed the building as nine square "tubes"-each essentially a separate building-clustered in a 3x3 matrix. All nine tubes would rise up to the 50th floor of the building. At the 50th floor, the northwest and southeast tubes end, and the remaining seven continue up. At the 66th floor, the northeast and the southwest tubes end. At the 90th floor, the north, east, and south tubes end. The remaining west and center tubes continue up to the 108th floor.
Sears executives decided early on that the space they would immediately occupy should be efficiently designed to house the small army that was their Merchandise Group. But floor space for future growth would be rented out to smaller firms and businesses until Sears could retake it. Therefore, the floor sizes would need to be smaller, and to have a high window-space to floor-space ratio, to be attractive and marketable to these prospective lessees. Smaller floor sizes necessitated a taller structure. Skidmore architects proposed a tower which would have large 55,000-square-foot (5,000 m²) floors in the lower part of the building, and would gradually taper the area of the floors down in a series of setbacks, which would give the Sears Tower its distinctive, husky-shouldered look.
As Sears continued to offer optimistic projections for growth, the tower's proposed height soared into the low hundreds of floors and surpassed the height of New York's unfinished World Trade Center to become the world's tallest building. Restricted in height not by physical limitation or imagination but rather by a limit imposed by the Federal Aviation Administration to protect air traffic, the Sears Tower was financed completely out of Sears' deep pockets and topped with two antennas to permit local television and radio broadcasts. Sears and the City of Chicago approved the design, and the first steel was put in place in April 1971. The structure was completed in May 1973. Construction costs totaled approximately $150 million USD at the time, which would be equivalent to roughly $950 million USD in 2005. For comparison, Taipei's Taipei 101, built in 2004, cost around the equivalent of US$1.76 billion in 2005 dollars.
Black bands appear on the tower around the 29th-32nd, 64th-65th, 88th-89th, and 104th-109th floors. These are louvers which allow ventilation for service equipment and obscure the structure's belt trusses which Sears Roebuck did not want to be visible as on the John Hancock Center.
In February 1982, two television antennas were added to the structure, increasing its total height to 1,707 feet (520 m). The western antenna was later extended to 1,730 feet (527 m)[6] on June 5, 2000 to improve reception of local NBC station WMAQ-TV.
6. Taipei 101
Taipei 101 has been the world's tallest building since 2004.[I]
Preceded by Petronas Twin Towers
Surpassed by Burj Dubai
Coordinates: 25°2′1″N 121°33′52″E / 25.03361°N 121.56444°E / 25.03361; 121.56444
Location Xinyi District, Taipei, Taiwan
Status Complete
Constructed 1999-2004
Use Mixed use: communication, conference, fitness center, library, observation, office, restaurant, retail
Height
Antenna/Spire 509.2 m (1,670.6 ft)
Roof 449.2 m (1,473.8 ft)
Top floor 439.2 m (1,440.9 ft)
Technical details
Floor count 101
Floor area 412,500 m2 (4,440,100 sq ft)
Elevator count 61, including double-deck shuttles and 2 high speed observatory elevators)
Cost NT$ 58 billion
(USD $ 1.76 billion)[1]
Companies
Architect C.Y. Lee & partners
Structural Engineer Thornton Tomasetti
Contractor KTRT Joint Venture, Samsung
Owner Taipei Financial Center Corp.
Management Urban Retail Properties Co.
Fully habitable, self-supported, from main entrance to highest structural or architectural top; see the list of tallest buildings in the world for other listings.
Taipei 101, also known as the Taipei Financial Center, is a landmark skyscraper located in Xinyi District, Taipei, Taiwan. The building became the world's tallest skyscraper upon its completion in 2004. as certified by the Council on Tall Buildings and Urban Habitat. Taipei 101, designed by C.Y. Lee & Partners and constructed primarily by KTRT Joint Venture and Samsung Engineering & Construction received the 2004 Emporis Skyscraper Award and was hailed as one of the Seven New Wonders of the World (Newsweek magazine, 2006) and Seven Wonders of Engineering (Discovery Channel, 2005). The tower is an icon of modern Taiwan. Fireworks launched from Taipei 101 feature prominently in international New Year's Eve broadcasts and the structure appears frequently in travel literature and international media.
Taipei 101 comprises 101 floors above ground and 5 floors underground. The name of the tower (pronounced "one oh one" in English) reflects its floor count and carries symbolic meanings alluding to technology and Asian tradition (see "Symbolism" below.) Its postmodernist approach to style incorporates traditional design elements and gives them modern treatments. The tower is designed to withstand typhoons and earthquakes. A multi-level shopping mall adjoining the tower houses hundreds of fashionable stores, restaurants and clubs.
7. Shanghai World Financial Center
The Shanghai World Financial Center is a supertall skyscraper in Pudong, Shanghai, China. It is a mixed use skyscraper which consists of offices, hotels, conference rooms, observation decks, and shopping malls on the ground floors. Park Hyatt Shanghai is the hotel component containing 174 rooms and suites. It is the highest hotel in the world, surpassing the Grand Hyatt Shanghai on the 53rd to 87th floors of the neighbouring Jin Mao Tower.
Location People's Republic of China Shanghai, China
Coordinates 31°14′12″N 121°30′10″E / 31.23667°N 121.50278°E / 31.23667; 121.50278Coordinates: 31°14′12″N 121°30′10″E / 31.23667°N 121.50278°E / 31.23667; 121.50278
Status Complete[1]
Constructed 1997 - 2008
Opening 2008
Use Office, hotel, museum, observation, parking garage, retail
Height
Antenna/Spire 494.4 m (1,622.0 ft) / 492.0 m (1,614.2 ft)
Roof 487.4 m (1,599.1 ft)[2]
Top floor 474.0 m (1,555.1 ft)
Technical details
Floor count 101
Floor area 381,600 m2 (4,107,500 sq ft)
Elevator count 91
Cost RMB ¥ 8.17 billion
(USD $ 1.20 billion)
Companies
Architect Kohn Pedersen Fox
Structural Engineer Leslie E. Robertson Associates RLLP
Contractor China State Construction Engineering Corp. and Shanghai Construction (Group) General Co.
Developer Mori Building Co.
On 14 September 2007 the skyscraper was topped out at 492.0 meters (1,614.2 ft) and became the second tallest building in the world; as well as the tallest structure in the People's Republic of China, including Hong Kong. It is currently the world's tallest completed building by roof.
On 28 August 2008, the SWFC officially opened for business. On August 30 the Observation Deck opened with a view from 3 levels. The highest view is at 474 m (1,555 ft) above ground level.
Designed by Kohn Pedersen Fox, the 101-story tower was originally planned for construction in 1997, but work was temporarily interrupted by the Asian Financial Crisis in the late 1990s and later to accommodate design changes by the developer. The building of the tower is financed by several multinational firms, including Japanese, Chinese, and Hong Kong banks, as well as by the Japanese developer and as-yet unnamed American and European investors. American investment bank Morgan Stanley is coordinating the financing for Mori Building.
The foundation stone was laid on 27 August 1997. In the late 1990s the Pierre de Smet Building Corporation had a fund shortage caused by the Asian financial crisis in 1997 to 1998, which halted the project after the foundations were completed. On 13 February 2003, the Mori Group increased th
