Bank of China Tower, known as the tallest building in Hong Kong and Asia from 1989 to 1992, is 1,209-foot and it is a fitting building.
The “Tower” sits in the central business district, a ribbon of land densely packed with banks and office buildings squeezed between mountain and harbor. It is one of the busiest, crowded, active, frenetic cities in the world. After experiencing it, I was attracted by its visual context and its special features, as this modern building has a flexible layout, reflective glasses, sustainability in architectural design……etc pic I.M. Pei, the architect of Bank of China Tower, tends to use large, abstract forms and sharp, geometric designs. His glass clad structures seem to spring from the high tech modernist movement. His reliance on abstract form and materials such as stone, concrete, glass, and steel, has been considered a disciple of Walter Gropius.
Nevertheless, he is more concerned with function than theory. Pei wanted to create a structure that would represent the aspirations of the Chinese people and symbolize good will toward the British people. His buildings are a unique testament to how the convergence of two great traditions, the Asian and the European, can create new aesthetic standards – timelessness in stone and glass. He has used the urban, modern style to create the building, such as steel frame and glass curtain wall.
Bank of China Tower is the most noticeable building in Hong Kong, not only the number of stories but is also the only building that stands out from the rest of the other buildings because of it extraordinary shape. Here come details of the Bank of China: |pic| |Glass Skyscraper | First of all, let us look back to 1883, William Le Baron Jenney invented the first “skyscraper construction” building, in which a metal structural skeleton supports an exterior wall on metal shelves (the metal frame or skeleton, a sort of three-dimensional boxlike grid, is still used today). His earliest surviving metal-skeleton structure, the Second Leiter Building of 1891, stands at the southeast corner of State and Van Buren streets in the Loop. The granite-face facade is extremely light and open, suggesting the metal frame behind.
The building looks so modern that it comes as a shock to realize it is more than a century old. On the other hand, Ludwig Mies van der Rohe’s structural and spatial concepts are analyzed through his three major building prototypes, specifically the skeleton frame building, both in its high- and low-rise manifestations, and the clear-span building. His most important projects are also examined, not only as isolated functions, but within the context of urban space. The ‘Seagram’ building in New York, hailed as a masterpiece of skyscraper design, which profoundly influenced the form and architecture of the office building, and the open space in the city. The extruded metal and glass curtain wall of Seagram and its use of tinted glass became widely replicated. After the Seagram building was completed and it encourages street-level open space in association with high-rise buildings.
According to Ken Yeang, skyscraper, as a city-in-the-sky, in a novel design approach that resembles urban design and planning as against the design of a conventional building in a high-rise structure. It is a new vertical theory of urban design. It also suggests ideas for the diversification of vertical land uses, the creation of public realms and places-in-the-sky, vertical landscaping, creating high-rise neighborhoods, vertical townscape, vertical transportation and accessibility. Structure engineer Leslie Robertson describes the tubes as “bundled vertical space trusses.” Almost the entire gravity load of the building flows through the structural diagonals behind the “Xs” of the facade to four corner columns. There is a fifth central column that splits into a tetrahedron at the twenty-fifth floor with branching legs that pass interior loads to the comer columns adding stability close to the base and the great clear span of the lobby. pic The diagonals, intermediate minor columns and beams, and stiffening trusses in different planes are framed into the primary comer columns.
The composite action steel and concrete comers lock the structural elements into a space frame structure, and this is what sets this building apart from others. |pic| The “Tower” is sustainability in architectural design. Reduce in energy consumption is not the only strategy of sustainable design. The resources / materials conservation as well as the environmentally pleasant design are good examples that can be observed in Bank of China Tower. Five principal columns hold up the 70-storey building with one at each of its four corners risen to different heights and a central column transferring loads down from the tower top to the 25th floor and then diagonally out to the corner columns. This structural system requires less major diagonal elements and lighter structural membering.
Reinforced concrete, instead of complex and expensive welded steel connection, was the element to envelop the joint at which vertical, horizontal and diagonal members of the steel frame come together from different angles. The 3-dimensional space truss together with the concrete joint let the tower use only 60% as much steel as a conventional skyscraper frame normally has used. It has a flexible layout. The triangularly trussed 3-dimensional structure gives column-free interior space that allows future change in office layout. This saves energy and resources.Talking about the lighting, atrium and the inclined roofs (skylight) allow more natural lighting and therefore save energy for artificial lighting: The 15-storey atrium running from the ground floor to the building’s first sloped roof makes possible the diffuse of natural light down to the banking hall.
“Sky lounge” on the 70th floor topped by an inclined triangular cap is also flooded by natural light. The building is covered by reflective glasses. The whole building is enclosed by silver-coated reflective glass framed in natural anodized aluminum. Such skin not only reflects the images of changing sky and city, but also the bright sunlight so that heat gain and cooling loads (i.e. energy consumption) were effectively reduced.
|pic| Masking effect of water gardens is found, the whole building has rotated by 45 degree, forming triangular spaces (water gardens) at either side of the entrance. The flowing water helps to muffle the noise from the busy traffic roads nearby and makes the entrance area more environmental friendly and welcoming. Composite design allows the geometry of the structure to be molded to the geometry of the facade. Pei insisted that the corners of the facade diagonals come to a point at the absolute edge of the building. The aluminum cladding does just that.
Behind the virtuoso precision of the curtain wall, the structure does what it has to do to hide itself. The building rises as a great cantilever out of the ground that must withstand lateral forces as a horizontal cantilever withstands vertical forces. In Hong Kong these are considerable. The tower will withstand double the wind loads of New York City – typhoon winds of 143 mph at the top and four times the equivalent earthquake load of Los Angeles.
Cantilever loads are greatest at the fixed end. The foundation is cast-in- place hand-dug concrete caissons with perimeter concrete diaphragm walls. The base of the Bank of China Tower is stabilized by two steel-plate shear tubes. These surround the service cores from foundation to fourth floor. Steel plates are generally less than one-half inch thick.
These provide the whole lateral force system from story four down. The shear cores include the elevators aid the bank vault areas where the steel is covered by over three feet of concrete. There are thinner concrete overlays elsewhere on the steel-plate shear tubes for interior building cladding. |pic | The “Tower” was very much an international effort.
“Green coated” reinforcing bars, used in selected areas of the building to combat electrolytic action, were a “first” in Hong Kong. The bars were purchased in China, shipped to Abu Dhabi for epoxy coating and then to Hong Kong. The curtain wall was bid by firms in West Germany, Japan, and the United States. The West German firm won the contract.
The building turns to different colors as the day goes by. Because of its steel frame and glass curtain wall, it reflects the day light. In the morning, the building’s color is glossy sky blue and at night is both black and gray with some night lights reflected from other building’s lights. While visually striking as a sculptural form, the tower was also an engineering breakthrough. By using an enormous version of a conventional three-dimensional truss as the basic structure, Pei was able to transfer stress to the four corners of the building, making it far more stable than it would have been if built according to the column-and-beam method. The Bank of China Tower differs in structural concept from the traditional buildings around it and looks it.
It is not politely nor politically contextual. It stands out as what it is, an ingenious architectural and structural solution symbolizing the Republic of China. The two are entirely different building concepts with little basis for comparison. Foster’s Hong Kong Bank is a highly hand- and machine-crafted jewel. It is tied into the great money market electronic network of world finance. The Bank of China Tower is a branch bank building in which most of the space is for rent, a commercial building.
The Bank of China will occupy floors one through seventeen and sixty-eight through seventy. Fifty- one floors are “spec. space” designed to be competitive on the Hong Kong market. |pic| The Bank of China Tower is very much a building of our time.
The Empire State Building and the Chase Manhattan Bank Building were designed before computers entered the building field to make number crunching cheap. At that time building forms were often changed to fit calculations. Ideas were discarded because they were too expensive to calculate. For years, as steel and concrete increased in strength, the changes were incorporated into building thinking as only improved versions of weaker steel and concrete. Their design was limited by conventional thinking. Columns could be made a bit smaller but no matter how much the strength of steel is increased the modulus of elasticity (stiffness) changes very little.
This means it becomes a better tensile material but not a great deal improved to withstand bending. Concrete has the opposite characteristic. Its compressive strength increases its tensile properties only grow as the square root of its compressive strength. The Bank of China at least involved fung shui. The people, representing an officially atheistic society were steadfastly opposed to the practice and refused to have the traditional analysis done. Not surprisingly, freelance advice began to proliferate almost as soon as the design was made public.
As if the unhappy history of the site was not curse enough, the local geomancers noted that the masts stop the tower could be interpreted either as chopsticks held vertically in an empty rice bowl, or as the sticks of incense used to memorialize of the dead. Far worse were the X’s made by the cross bracing that was to be expressed on the facades. Local authorities noted immediately that, at best, the X’s evoked the mark traditionally drawn on a failing student’s exercise by a calligraphy instructor. At worst, they suggested the custom of hanging a name tag around a condemned man’s neck and slashing an X through it to signify that he was “finished”. Coping with the unusual shape was a powerful motivation, an inspiration, in the development of this new concept. The system is now tested and ready for application to a wide variety of building systems.
pic It shows how the bank of china is joined together in 3 dimensions One has the impression it was over designed and excessively detailed. In contrast a structure as elegantly rational as the Bank of China Tower fits together in any language. So, Bank of China Tower is worthwhile to have further investigations. I have tried to discover what I have experienced, instead of observing some architecture I have never seen before.
Reference
Books: Donovan, M.
(2001)The architecture of I.M.PEI. Lordon: HarryN.Abrams, Inc. Whitney, J (1953) The Museum of Modern Art, New York: The Museum Von Boehm G (1990) Conversations with I.M.PEI Light is the key, New York Betsky, A (1992) Architecture and Medicine: I.M. Pei designs the Kirlin Clinic. University of Alabama Health Services Fenestration at the University at Birminham Medical Center: University Press of America Pei I M (1963) Urban Renewal in Southwest Washington. AIA Journal Wiseman, C (1990) A Profile in America Architecture.
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