Council on Tall Buildings and Urban Habitat

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The Council on Tall buildings and Urban Habitat (German: Council for tall buildings and urban living space ; abbreviation: CTBUH ) is an office of the Illinois Institute of Technology in Chicago , which deals with the assessment of the tallest buildings ( skyscrapers ) in the world and rules set up for it. Chairman of the CTBUH, founded in 1969 by engineer Lynn S. Beedle (1917–2003), is Antony Wood.

criteria

Tower peaks like those on the Petronas Towers are assessed by the CTBUH as part of the building and thus at the official height ...
... but antennas like on the Willis Tower are not

The Council on Tall Buildings and Urban Habitat defines a building as a “frame structure with walls and floors” , the “structural upper edge” of which is decisive for the height comparison.

According to the definition of the CTBUH, transmission masts and towers are not referred to as buildings. The tallest man-made structure is the Burj Khalifa in Dubai with a height of 828 meters.

According to CTBUH, the height of a building is measured from the sidewalk in front of the main entrance to the highest architectural element. Antennas attached are not included.

For the measurement of the height of a building, the CTBUH has established four categories, the first of which is considered to be the decisive criterion:

Structural height

The structural height is measured according to the highest architectural or integral element of the building. All parts of the building that are optically or statically essential components of the building are referred to as architectural elements. These include, for example, peaks, fixed structures and balustrades , which the architect envisaged as an integral part of the building concept, but not merely attached antennas, the distance of which would not significantly change the building either visually or statically. The distinction cannot always be made clearly, which is why this measured variable is highly controversial. For example, the antennas of the Willis Tower do not count towards the structural height, whereas the tips of the Petronas Towers do . Therefore, according to this measurement method, the Petronas Towers are higher than the Willis Tower, although the latter has the higher accessible floor and the higher antenna tip. A similar conflict arises with the Commerzbank Tower and the Triumph Palace in the competition for the tallest building in Europe. Despite difficulties in delimitation and the occasional appearance of arbitrariness, this height is used by most architectural firms that create rankings and is therefore the most frequently used for classification. As a result, this measurement criterion in turn influences the architecture itself: In the race for the highest possible list position, new super skyscrapers are usually designed in such a way that the antennas become optically essential building components.

Highest accessible floor

Here, the height is counted up to the ceiling of the highest floor that can be entered and used normally. Purely technical rooms that are only occasionally used for maintenance or repair purposes do not count. Due to the first category, the Petronas Towers in Kuala Lumpur are higher than the Willis Tower (until July 2009 Sears Tower) in Chicago, although its highest floor is 60 meters higher than the highest floor of the Petronas Towers.

Roof height

The roof height is the height to the highest point on the roof. The disadvantage of this measurand is that it is often very difficult to decide where the roof ends and where the tips begin. This category has therefore not been used since November 2009.

Total height

The total height indicates the absolute highest point of a building. In doing so, attached antennas are also taken into account, which, however, are not used in official listings. Using this measurement method there are some changes to the list of tallest buildings.

The Burj Khalifa is a skyscraper that has been the tallest building in the world since July 2007. Investors tried for a long time to keep the height of the tower and the number of floors a secret. It reached its final height of 828 meters on January 17, 2009, and was inaugurated on January 4, 2010. The building is record holder in all categories.

Number of floors (above ground)

This height specification indicates the height of the highest occupied floor above the ground.

further criteria

In addition to the height measurement, the CTBUH defines further criteria for the evaluation of skyscrapers. This includes the use, the status and the building material.

use

Single use is given if at least 85 percent of the building's usable area is used for a single function (e.g. offices). A mixed use is when each at least 15 percent of two or more features takes to complete. Technical bullets are excluded from this rating. Offices, apartments, hotel rooms, shopping centers or exhibition areas are regarded as uses.

status

The CTBUH also defines individual categories for the status of a building:

  • Built (complete) : The building is built, i.e. H. the final height has been reached and the building is at least partially released for use.
  • Final height achieved (topped out) : The building is still under construction, has already reached its maximum height.
  • Under Construction (under-construction) : The building is under construction. Work on the foundations must have started. Construction site preparations are not counted for this.
  • Construction stopped (construction stopped) : The building was under construction, but the work was stopped again. The reasons for this are mostly economic in nature.
  • Planned / proposed (Proposed) : It is planned to erect the building. Before a building falls into this category, however, a few things must be considered: The building must have a draft (professional design), a potential construction site and a project developer or investor.
  • Never built (never built) : These include building either visionary plans are or repealed or revoked projects.
  • Destroyed / demolished (demolished) : The building, however, no longer existed at an earlier time, now. It was demolished or destroyed.

Building material

The CTBUH also defines the material of the building. This is about the load-bearing structural element of the skyscraper: a building whose ceilings are made of concrete, but the load-bearing support elements are made of steel, counts as a steel building.

  • Steel (steel) : All horizontal and vertical support members of the building are made of steel. This construction method was mainly used earlier and is only used occasionally today. Most of the steel buildings can be found in the USA, but also in China.
  • Concrete (concrete) : All horizontal and vertical support members of the building are made of reinforced concrete. Mostly this can be found in residential buildings. Most of these buildings can be found in the Middle East (but also in Europe, occasionally in North America and Asia).
  • Composed (composite) : The horizontal and vertical support elements consist of a mixed structure of steel and concrete. Usually it is a solid concrete core and steel pillars on the facade. While this construction method was still used sporadically in the 1990s, many skyscrapers of the 21st century are being built using this construction method.
  • Concrete (concrete-steel) and concrete steel (steel-concrete) : In addition, there are still building having a concrete structure in the lower part, above which a steel structure follows (so when Burj Khalifa). Other buildings, on the other hand, have a steel structure below, the upper part was then built in concrete. This design is now also found relatively often.

Database

Since January 2010 the CTBUH has been offering a new building database. There you can compile a number of rankings according to different criteria (use, material, year of construction, location, etc.), which are always based on the CTBUH rules. Each of the more than 10,000 buildings in the database has its own page on which you can see the most important information about the building.

Height Committee

The height of Chicago's Trump Tower had to be corrected in 2009 due to the measurement from the lowest entrance

The height committee is made up of various people and advises on general height measurements of buildings. This group is also entitled to change the existing criteria, for example it was decided in 2009 to abolish the category of "height to the roof", as it is increasingly difficult to determine the roof in newer buildings. The Height Committee also makes decisions about where a building will be measured from, so the height of Chicago's Trump Tower has been corrected from 415 meters to 423 meters, as the Height Committee decided that the tower must be measured from another entrance.

See also

Other websites with building databases

literature

  • Fazlur R. Khan, Walter P. Moore: Tall Building Systems and Concepts. American Society of Civil Engineers, 1980, ISBN 0-87262-239-8 .
  • Andres Lepik: Skyscraper. Prestel Verlag, Munich 2005, ISBN 3-7913-3454-9 .

Web links

Individual evidence

  1. ↑ a b c d CTBUH: Criteria Retrieved March 23, 2010
  2. ↑ Information on the height committee: ctbuh.org Accessed on March 23, 2010
  3. ↑ Information on the change in height. Accessed on March 23, 2010