Shanghai Tower was never going to be an ordinary skyscraper. Commissioned by the Chinese government, it was to be a soaring statement about the city and country’s growing economic prominence. It would be the tallest building in the nation and the second tallest on the planet. As the third in a trio of supertall structures in Shanghai’s financial district, it needed to complement its predecessors while looming over them. It had to be iconic, a model of sustainability, and a futuristic answer to the country’s rapid urbanization–a vertical city.
In order to satisfy these lofty and varied requirements, Gensler’s Jun Xia, the project’s lead designer, knew “the design had to be simple.” He and his team settled on a single unifying idea: an elegant spiral stretching skyward. The estimated $2 billion–plus tower, which opens next year, is a marvel of design and engineering–not to mention vegetation.
Shanghai Tower consists of a pillarlike building containing offices, a luxury hotel, restaurants, and retail stores–all encased in a triangle-shaped glass shell.
Two thousand feet above the ground, explains lead architect Dan Winey, “the wind can do some interesting things.” After testing more than a dozen models in a Toronto wind-tunnel lab, Gensler arrived at the most effective shape for the tower, a tapering spiral with a rotation of 120 degrees; a deep notch running its length interrupts the wind as it swirls around the building. Together, the features reduce wind loads by 24%, which meant less steel and concrete were needed to stiffen and strengthen the building itself, saving $58 million.
Throughout construction, Winey would periodically ask, “How are we going to build this?” He wasn’t being rhetorical. Because of the tower’s twisting design, builders had to identify where each panel in the outer glass wall would go before it could be fabricated, and traditional measuring techniques couldn’t achieve the necessary precision. The Gensler team was forced to position lasers on adjacent buildings to triangulate the 20,327 points where exterior panels would be installed. “There wasn’t a day that didn’t go by that I didn’t learn something,” Winey says.
The gold LEED–certified tower incorporates several dozen features–such as 270 wind turbines, which help power its nighttime lighting, and a rainwater collection system–to reduce overall energy consumption by 21%.
To alleviate sway, Shanghai Tower has a record 1,200-ton “tuned mass damper” at the top; controlled by software, it acts as a counterweight, shifting as the building moves to bring it back to vertical. An artist is turning this engineering feat into a sculpture, complete with its own observation area.
Between the lower-level conference and retail area and the top-floor observation deck, Shanghai Tower is divided into seven zones. Five have offices; two house a luxury hotel. Each section has a main floor with stores, restaurants, and open spaces–a plaza in the sky.
On each zone’s main floor, be-tween the inner core and the wraparound glass wall, are three atria, up to 60 feet wide and 14 stories tall. These 21 indoor parks, visible from outside the tower, will feature local vegetation and trees that will provide fresh air and help regulate the building’s temperature.
Cities are about exploration, says Jun, but high-rises often are not. He hopes that elevator transfers on the atrium floors, from express to local, will encourage discovery. “That’s how I grew up in Shanghai,” Jun says. “You walk along a major street, into an intimate alley, through a courtyard,” then home.