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Fazlur Rahman Khan, a Bangladeshi-American structural engineer, made very tall buildings cheaper to build with his 'tube' systems, in which a tower's outer walls work together to resist the wind. They shaped Chicago's John Hancock Center and the Sears Tower, now Willis Tower.

Fazlur Rahman Khan

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The story behind the card

Before Khan, most skyscrapers relied on a rigid internal frame of steel columns and beams, and the taller they went, the more steel they needed to keep them from swaying in the wind. In Khan's framed tube, columns are set close together around the outside of the building and tied by deep beams called spandrels, so the whole outer wall acts like one stiff, hollow tube anchored in the ground. Working at the Chicago firm Skidmore, Owings & Merrill, he developed variations: the John Hancock Center (1969) braces its tube with giant diagonal X-shapes, and the Sears Tower (1973) bundles nine tubes together. Khan was born in Dhaka in 1929 and died in 1982.

Türkçe oku
Bangladeş asıllı Amerikalı yapı mühendisi Fazlur Rahman Khan, geliştirdiği “tüp” sistemleriyle çok yüksek binaları daha ucuza yapılabilir hâle getirdi. Bu sistemlerde kulenin dış duvarları birlikte çalışarak rüzgâra karşı koyar. Chicago'daki John Hancock Center ile bugünkü adı Willis Tower olan Sears Tower bu fikirle yükseldi.

Khan'dan önce gökdelenlerin çoğu, içeriden çelik kolon ve kirişlerle kurulan sağlam bir iskelete dayanıyordu; bina yükseldikçe rüzgârda sallanmaması için gereken çelik de artıyordu. Khan'ın çerçeveli tüp sisteminde kolonlar binanın dış çevresine sık aralıklarla dizilir ve derin kirişlerle birbirine bağlanır. Böylece bütün dış duvar, zemine sağlamca oturmuş, içi boş ve rijit tek bir boru gibi davranır. Chicago'daki Skidmore, Owings & Merrill firmasında bu fikrin farklı biçimlerini geliştirdi: John Hancock Center'da (1969) tüp, cepheye yerleştirilmiş dev X biçimli çaprazlarla güçlendirildi; Sears Tower'da (1973) ise dokuz tüp bir demet gibi bir araya getirildi. Khan 1929'da Dakka'da doğdu, 1982'de öldü.

Sources and further reading

Background reading: Fazlur Rahman Khan
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