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WonderStructural dynamics fact

Near the top of Taipei 101 hangs a 660-tonne steel sphere that swings against the tower's sway in strong wind, so people inside feel much less movement. Engineers call this device a tuned mass damper.

Tuned mass damper

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The story behind the card

Taipei 101, a 508-metre skyscraper in Taiwan's capital, opened in 2004. Its gold-painted sphere is 5.5 metres across and hangs from the 92nd down to the 88th floor, where visitors can see it. The ball is tuned to the tower's own natural rhythm of swaying but moves out of step with it, so each push of the wind is partly cancelled, while hydraulic dampers turn the motion into heat. It can reduce the building's movement by up to 40 per cent. During Typhoon Soudelor in August 2015 the ball swung a record one metre. Smaller tuned dampers steady bridges, chimneys and power lines; London's Millennium Bridge was fitted with them after it wobbled under crowds when it opened in 2000.

Türkçe oku
Taipei 101'in üst katlarında 660 tonluk çelik bir küre asılıdır. Sert rüzgârda kule bir yana yattığında küre ters yöne salınır ve içeridekiler sallantıyı çok daha az hisseder. Bu düzeneğin adı ayarlı kütle sönümleyicidir.

Taipei 101, Tayvan'ın başkentinde 2004'te açılan 508 metrelik bir gökdelendir. Altın rengine boyanmış küre 5,5 metre çapındadır; 92. kattan 88. kata kadar sarkar ve ziyaretçiler onu yakından görebilir. Küre, kulenin kendi doğal salınım hızına göre ayarlanmıştır ama onunla ters zamanda hareket eder; böylece rüzgârın her itişini kısmen dengeler. Hidrolik sönümleyiciler de bu hareketi ısıya çevirerek söndürür. Sistem binanın sallanmasını yüzde 40'a kadar azaltabilir. Ağustos 2015'teki Soudelor tayfununda küre 1 metre salınarak rekor kırdı. Daha küçük sönümleyiciler köprülerde, bacalarda ve elektrik hatlarında da kullanılır. Londra'daki Millennium Köprüsü, 2000'deki açılışında kalabalığın adımlarıyla sallanınca bu düzeneklerle donatıldı.

Sources and further reading

Background reading: Tuned mass damper
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