Looking at first glance like a set of futuristic renders, these two skyscrapers are very much real and in use in China. They have just been named the Best Tall Building Worldwide for their extraordinary exoskeleton exteriors, which cleverly respond to high winds and earthquakes.
Designed by Skidmore, Owings & Merrill (SOM), with the Beijing Institute of Architectural Design, the Sany Irootech Headquarters was commissioned by construction machinery giant Sany. It consists of two skyscrapers rising to a height of 204 m (679 ft) and 186 m (610 ft), respectively, and is located in the bustling port city of Guangzhou, in Guangdong Province.
Concern over wind and seismicity played an important role in shaping the design. Each building features an exposed hexagrid arranged in an irregular, diagonal pattern, with greenery integrated into the facade. The hexagrid is formed by concrete-filled steel tube columns, with four of every five floors hung from the frame to create column-free, daylit floors, ensuring lots of flexibility inside.
"For tall buildings, the most efficient structure for lateral load resistance uses members in axial compression or tension, but that system isn't ductile when an earthquake comes," explains Mark Sarkisian, structural and seismic engineering consulting partner at SOM.
"So we needed a system that is stiff for daily wind and moderate seismic movement but softens when the extreme earthquake comes, which could be 10 times the demand from the wind. Instead of yielding and damaging the steel, we clamped common steel plates together with a friction material within the horizontal sections of the building's offset bracing, so in a big earthquake the bracing slides and dissipates the energy through friction and heat, like pressing the brake on your car. We believe it's the future of seismic design for tall buildings."
The buildings' interiors host office spaces, along with a hotel and some residential units. Landscaped terraces are placed at five-floor intervals, providing communal outdoor spaces while also shading the interiors and reducing solar radiation on the facade. The buildings also incorporate passive cooling, including operable vents and glass doors to allow natural ventilation. Additionally, an elevated podium spanning the towers frees up the ground for a public plaza with gardens and art.
The Sany Irootech Headquarters was named Best Tall Building Worldwide at an awards ceremony held by the Council on Vertical Urbanism (formerly known as the CTBUH) in London this week.
Source: Council on Vertical Urbanism
