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DriveEarthquake engineering fact

Some buildings in earthquake zones do not sit directly on their foundations but on flexible bearings made of rubber and steel. When the ground shakes, the bearings take up most of the movement and the building above sways far more gently. Engineers call this seismic base isolation.

Seismic base isolation

EngineeringArchitectureTechnologyScience

The story behind the card

A conventional building is tied rigidly to the ground, so it takes on almost every jolt. In an isolated building, bearings separate the structure from its foundation. They are usually stacked layers of rubber and steel, often with a lead core that soaks up energy; the lead-rubber bearing was invented in New Zealand by Bill Robinson in 1974. Because the building shifts slowly on its bearings, upper floors feel much weaker shaking and equipment inside is more likely to keep working. The building needs a gap around it so that it can move, and its pipes and cables need flexible joints. San Francisco City Hall, Wellington's Te Papa museum and, in Istanbul, the Sabiha Gökçen Airport terminal and Başakşehir Çam and Sakura City Hospital all stand on isolators.

Türkçe oku
Deprem bölgelerindeki bazı binalar doğrudan temele oturmaz; kauçuk ve çelik katmanlardan yapılmış esnek yastıklar, yani izolatörler üzerinde durur. Zemin sarsıldığında hareketin büyük kısmını bu yastıklar karşılar, üstteki bina çok daha yumuşak salınır. Bu yönteme sismik izolasyon denir.

Sıradan bir bina zemine sıkıca bağlıdır; bu yüzden her sarsıntıyı neredeyse olduğu gibi yaşar. İzolasyonlu bir binada ise yapı ile temel arasında izolatörler bulunur. Bunlar genellikle üst üste dizilmiş kauçuk ve çelik katmanlardan oluşur, çoğunun ortasında enerjiyi emen bir kurşun çekirdek vardır. Kurşun çekirdekli kauçuk izolatörü 1974'te Yeni Zelandalı mühendis Bill Robinson geliştirdi. Bina izolatörlerin üzerinde yavaşça kaydığı için üst katlar sarsıntıyı çok daha hafif hisseder, içerideki cihazların çalışmayı sürdürme şansı artar. Binanın çevresinde hareket payı bırakılır, borular ve kablolar esnek bağlantılarla döşenir. San Francisco Belediye Binası, Wellington'daki Te Papa Müzesi, İstanbul'da da Sabiha Gökçen Havalimanı terminali ile Başakşehir Çam ve Sakura Şehir Hastanesi izolatörler üzerinde durur.

Sources and further reading

Background reading: Seismic base isolation
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