The St. Francis Shangri-La Place - Structural Dampers

Structural Dampers

Due to the tower's location being close to an active fault in a highly seismic region and also subjected to typhoon winds, the St. Francis Shangri-La Place was the first building in the world to feature a revolutionary ‘damping’ system designed by international engineering company Ove Arup & Partners. The new system, which minimizes the standard wobble in high-rise buildings, employs the same technology used to strengthen the Millennium Bridge in London. This makes the St. Francis Shangri-La Place one of the safest buildings.

The usual methods employed to strengthen buildings are to reinforce it with significant extra structure or to install tuned mass dampers. Both methods are not only expensive, but also make the building stiffer and heavier while consuming valuable space. The Arup solution works by inserting Viscous Dampers into the St. Francis Shangri-La Place to act as energy absorbers and damp out vibrations. Viscous dampers connect deep reinforced concrete outriggers from the central core of each building to the perimeter columns at one level. The added damping so derived, in excess of 6% of critical controls wind-induced motions, achieving occupant comfort objectives, and reduces the design wind overturning moment by a factor of 1.7. Not only is this a lower-cost solution, it is also more sustainable as it uses less material, and leaves more valuable space inside the building.

Reductions in the quantities of concrete and reinforcing steel in the St Francis Towers structure due to the incorporation of the Arup damping system and performance based seismic design saved the building's developer in excess of $5 million in construction cost and more net floor space (through smaller columns and core walls, and no need for space for TMDs).