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The current legal building name.
Other names the building has commonly been known as, including former names, common informal names, local names, etc.
CTBUH collects data on two major types of tall structures: 'Buildings' and 'Telecommunications / Observation Towers.' A 'Building' is a structure where at least 50% of the height is occupied by usable floor area. A 'Telecommunications / Observation Tower' is a structure where less than 50% of the structure's height is occupied by usable floor area. Only 'Buildings' are eligible for the CTBUH 'Tallest Buildings' lists.
The CTBUH follows the United Nations's definition of Country, and thus uses the lists and codes established by that organization.
The CTBUH follows the United Nations's definition of City, and thus uses the lists and codes established by that organization.
A single-function tall building is defined as one where 85% or more of its usable floor area is dedicated to a single usage. Thus a building with 90% office floor area would be said to be an "office" building, irrespective of other minor functions it may also contain.
A mixed-use tall building contains two or more functions (or uses), where each of the functions occupy a significant proportion of the tower's total space. Support areas such as car parks and mechanical plant space do not constitute mixed-use functions. Functions are denoted on CTBUH "Tallest Building" lists in descending order, e.g., "hotel/office" indicates hotel function above office function.
Both the main vertical/lateral structural elements and the floor spanning systems are constructed from steel. Note that a building of steel construction with a floor system of concrete planks or concrete slab on top of steel beams is still considered a “steel” structure as the concrete elements are not acting as the primary structure.
Both the main vertical/lateral structural elements and the floor spanning systems are constructed from concrete which has been cast in place and utilizes steel reinforcement bars.
Both the main vertical/lateral structural elements and the floor spanning system are constructed from steel reinforced concrete which has been precast as individual components and assembled together on-site.
Utilizes distinct systems (e.g. steel, concrete, timber), one on top of the other. For example, a steel/concrete indicates a steel structural system located on top of a concrete structural system, with the opposite true of concrete/steel.
A combination of materials (e.g. steel, concrete, timber) are used together in the main structural elements. Examples include buildings which utilize: steel columns with a floor system of reinforced concrete beams; a steel frame system with a concrete core; concrete-encased steel columns; concrete-filled steel tubes; etc. Where known, the CTBUH database breaks out the materials used in a composite building’s core, columns, and floor spanning separately.
Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the architectural top of the building, including spires, but not including antennae, signage, flag poles or other functional-technical equipment. This measurement is the most widely utilized and is employed to define the Council on Tall Buildings and Urban Habitat (CTBUH) rankings of the "World's Tallest Buildings."
The number of floors above ground should include the ground floor level and be the number of main floors above ground, including any significant mezzanine floors and major mechanical plant floors. Mechanical mezzanines should not be included if they have a significantly smaller floor area than the major floors below. Similarly, mechanical penthouses or plant rooms protruding above the general roof area should not be counted. Note: CTBUH floor counts may differ from published accounts, as it is common in some regions of the world for certain floor levels not to be included (e.g., the level 4, 14, 24, etc. in Hong Kong).
Erected during a building boom underway in Melbourne during the 1950’s, the ICI Building, as Orica House was originally known, was the first proposal to challenge regulations limiting height in Australian cities. When the plan for Orica House was first introduced in 1955, Melbourne’s buildings were limited to 11-12 stories in height. Influenced by the form of American office building constructed in the early 1950s, the building was proposed to cover only a portion of the site, leaving the remainder as a setback plaza and landscaped garden, positioned as a public amenity and trade off in exchange for surpassing the previously imposed height restriction. The building was then approved in 1957 and led to Melbourne becoming the first Australian city to revise its height limitations in which taller buildings were allowed in individual circumstances, often contingent on light angles.
Upon completion, Orica House had the highest floor count of any office building in Australia and is today listed as a National Heritage site. Subsequent building retrofits have been sensitive to retrain the aesthetics of the international style building while improving energy efficiency and adapting the structure for the demands of today’s users.