How Taiwan's tallest building survived the earthquake: Taipei 101 has a ... trends now
Taiwan has been hit by its strongest earthquake in 25 years, killing at least nine people, toppling buildings and even triggering tsunami warnings.
But amid the chaos, eerie footage shows the island's tallest building – the $1.8 billion Taipei 101 skyscraper – gently swaying like a stick in the breeze.
Measuring 1,671 feet in height, the building is fitted with an ingenious solution that reduces overall building sway by 40 per cent during quakes and winds.
A 660 metric ton golden sphere called the 'tuned mass damper' hangs inside the building from the 92nd floor.
As the building moves in one direction, the steel sphere sways in the other direction and maintains the building's overall balance.
Key to Taipei 101's impressive structural integrity is a 660 metric ton golden sphere that hangs from the 92nd floor
If wind or the force of an earthquake pushes the tower to the right, the sphere will provide an immediate and equal force to the left, cancelling out the initial motion.
So although the tower sways, it doesn't topple.
It's what's known as a 'passive damping system' meaning it operates without any external power or control – just gravity and the movement of the building.
Meanwhile, hydraulic pistons underneath the massive sphere absorb and dissipate the energy as heat.
Dr Agathoklis Giaralis, a professor of structural dynamics at City, University of London, described the clever spherical device as 'like a pendulum'.
'This steel sphere rests on damping devices which are designed to dampen the relative sway movement between the structure and the sphere, acting in a similar way to the shock absorbers in car suspensions,' he told MailOnline.
Although it's odd to see a building swaying, modern skyscrapers are built to be flexible, especially in earthquake-prone zones like Taiwan.
'The materials they are made out of are elastic which means that they stretch or contract according to the changing loads acting on them,' Professor Antony Darby at the University of Bath's Department of Architecture and Civil Engineering told MailOnline.
'The amount of this deformation in an individual element (e.g. a beam or column) is only very small, but when you multiply this across all the elements in a tall building, this can lead to significant lateral [sideways] movements.
'These movements are not dangerous to the structure itself, but, if excessive can lead to discomfort to occupants.'
Taipei 101 is the tallest building in Taiwan and formerly the tallest building in the world (now the 11th tallest)
Key to the building's amazing structural integrity is a 660 metric ton golden sphere that hangs from the 92nd floor - the 'tuned mass damper'
In Taiwan, Taipei 101 must stand up to earthquakes and typhoons. Every eight floors the building was installed with supporting steel 'outrigger trusses' running from the building's core to its outer columns to increase the towers
