Giant Ball Bearings- Quake-Insulators!

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A new breed of ball bearing has evolved for a very exclusive purpose! Where do you findgiant stainless-steel ‘spherical’ bearings with 15.71-foot girths?  They are found in earthquake proneplaces undergoing seismic retrofits.

Earthquakes happening on ‘the ring of fire’, located in the Pacific basin,  havebrought real fear to the hearts of those living in the fringes of the San Andrea fault line as they wait for The Big One. The recent earthquakes in Christchurch, New Zealand saw some 23,000 people move rather than take the risk of what could happen in the future. Yet, over forty countries have been determined to be at risk from earthquakes in this area.

Few have the choice to relocate. Cities remain, ready to be rebuilt and reoccupied. Earthquake prone California leads the change in research and earthquake engineering. All new commercialstructures are now required to meet strict earthquakeproof codes. To put it basically, all new structures must be able towithstand a certain degree of shaking and not collapse.

The burst of growth in the technology of earthquake-proofing buildings has resulted in the humble but polished performance of the ubiquitous ball bearing being one of the stars! And it is a big star! Older engineering dictated a rigid supporting base. But, now a base which permits movement has allowed architectural structures to retainintegrity and thus save human life. The San Francisco International Airport showcases new sophisticated building technology.

The total weight of the airport rests upon 267 columns and accompanying 5-foot diameter, steel ball bearingsinstalled at their bases. Each bearing rests within a concave basis, allowing the ball bearing to roll and move 20 inches in any direction when power is applied. During an earthquake, the lower plate moves in accordance with thefloor. With the ball bearing appearing as a buffer to the higher surface, the motionoccurring above is greatly diminished. Once at rest, gravity functions to realign the columns back to their resting point at centre base. 

Other equivalent engineering presently being used in Japan permits skyscrapers to ‘float’ using a technique  called “base isolation”. Building columns rest on systems of ball bearings, springs, and padded cylinders. If you were to rub the palms of your hands together in a circular motion, you would be able to mimic the movement of these systems gliding over the ball bearings.

Buildings therefore acquire a resilience, which can guard them from the full force of a quake. With this technology, buildings are made to possibly resist quakes measuring 8 on the Richter scale, therefore minimizing damage and lowering repair bills!

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