For decades, engineers have treated movement as the enemy of tall buildings. The taller a tower becomes, the more it sways in strong winds or during an earthquake, so the traditional solution has been straightforward: make the structure stiffer, stronger and heavier.
Researchers at Imperial College London and engineering consultancy Arup believe there’s another way.
Instead of trying to stop a skyscraper from moving altogether, they have developed a system that allows part of the building to move in a controlled way, using its own weight to reduce vibrations caused by high winds and earthquakes. The approach could improve safety while reducing the amount of concrete and steel needed to construct tall buildings.
The idea takes inspiration from an unlikely source. Traditional Japanese pagodas have survived centuries of earthquakes thanks in part to a central column that moves independently from the surrounding structure, helping to dissipate energy during seismic events.
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The new concept applies a similar principle to modern skyscrapers.
Rather than installing a conventional tuned mass damper – a huge suspended weight often placed near the top of a building to counteract swaying – the researchers turned part of the building itself into the damping system. A group of usable floors near the top of the tower is separated from the central core and connected using springs and dampers, allowing those floors to move slightly and absorb energy as the building sways.
Unlike traditional tuned mass dampers, which are primarily designed to improve comfort in high winds, the new system is intended to reduce movement caused by both wind and earthquakes. That means a single solution could replace multiple structural control systems in buildings exposed to both hazards.
To test the idea, the team built a 1:300 scale model of a 300 m tower and carried out wind tunnel testing at Imperial’s National Wind Tunnel Facility, alongside dynamic earthquake simulations in the university’s Structures Laboratory.
The results were encouraging. Wind-induced peak accelerations fell by as much as 71%, while the forces transferred to the base of the structure were reduced by more than half. During simulated earthquakes, movement at the top of the building fell by an average of 42%, and movement within the suspended floors was reduced by up to 74%. The researchers also found that the controlled motion would be small enough for occupants not to notice during normal operation.
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The concept relies on established engineering components, including springs, dampers and bearings already widely used in modern construction, rather than entirely new technologies. Because the system reduces the forces acting on the structure, engineers could also reduce the amount of material needed in the building’s core, columns and foundations, cutting both construction costs and embodied carbon.
That could become increasingly important as cities continue building taller structures in regions exposed to both strong winds and seismic activity. Many rapidly growing urban centres across East and Southeast Asia and Latin America face both hazards, making efficient structural control an increasingly important design challenge.
The researchers now plan to test the system at a larger scale before exploring its use on a real building.
More broadly, the work reflects a gradual shift in structural engineering. Rather than designing buildings that resist every force through sheer stiffness, engineers are increasingly finding ways to work with movement instead. Sometimes allowing a structure to move a little can make it perform a great deal better.