Engineering researchers at City University in London are developing new vibration-control devices, harnessing technology used in Formula 1 racing, to develop “needle-like” skyscrapers capable of resisting high winds.
Currently, tall buildings are fitted with devices called tuned mass dampers (TMDs) at the top floors to act as heavyweight pendulums counteracting building movement caused by winds and earthquakes.
But TMDs can weigh up to 1,000 tons and span five storeys in 100-storey buildings – adding millions of pounds to building costs and using up premium space in tight city centres.
New research work published by structural dynamics expert Dr Agathoklis Giaralis in the Engineering Structures journal found that lightweight and compact inerters, similar to those developed for the suspension systems of Formula 1 cars, can reduce the required weight of current TMDs by up to 70%.
Tests conducted by the researchers have shown that up to 30% less steel would needed in beams and columns of typical 20-storey steel building thanks to the new devices. Computer model analyses for an existing London building, the 48-storey Newington Butts in Elephant and Castle, Southwark, had shown that “floor acceleration” – the measure of occupants’ comfort against seasickness – can be reduced by 30% with the newly proposed technology.
Dr Giaralis said: “If we can achieve smaller, lighter TMDs, then we can build taller and thinner buildings without causing seasickness for occupants when it is windy. Such slender structures will require fewer materials and resources, and so will cost less and be more sustainable, while taking up less space and also being aesthetically more pleasing to the eye. In a city like London, where space is at a premium and land is expensive, the only real option is to go up, so this technology can be a game-changer.
“This reduction in floor acceleration is significant. It means the devices are also more effective in ensuring that buildings can withstand high winds and earthquakes. Even moderate winds can cause seasickness or dizziness to occupants and climate change suggests that stronger winds will become more frequent. The inerter-based vibration control technology we are testing is demonstrating that it can significantly reduce this risk with low up-front cost in new, even very slender, buildings and with small structural modifications in existing buildings.”
He added that as well as reducing carbon emissions thanks to the use of fewer materials, the new inerters could also be used to harvest energy from wind-induced oscillations. “I don’t believe that we are able at the moment to have a building that is completely self-sustaining using this technology, but we can definitely harvest enough for powering wireless sensors used for inner building climate control,” he said.
