A crowning achievement and symbol of the skyline of a world financial capital, the Shanghai Tower is filled with superlatives. China's tallest structure and the second-tallest building in the world, the recently topped-out 2,073-foot-tall tower contains the world's fastest elevator, which rockets up 121 stories at a top speed of 40 miles an hour (the cable is so long, it's the heaviest part of the elevator). The 18-foot-thick concrete slab at the core of the tower was the largest continuous pour on record, requiring three full days. Yet in the long run, those may not stand as the most lasting achievements of the building. According to project manager Grant Uhlir of Gensler, it's the sustainable features of this mixed-use structure—the "sky garden" concept that will introduce green living more than a thousand feet above the city streets—that may change how we construct and conceive of cities. How many supertalls shoot for LEED status?
"With these gardens, you don't have to go down to street level," says Uhlir. "You can grab a cup of coffee and walk among the trees in the sky."
The Shanghai Tower's unique design will end up with an energy savings of 21-22 percent over a skyscraper of comparable size. This reduction is achieved with the unique size and scope of the building, as well as a series of wind turbines near the crown that will provide enough power every year to cover the building's exterior lighting. The structure's curved spine redirects the wind force and allows for a lighter, less resource-intensive construction, while the unique double-skin glass façade will help insulate and reduce energy use.
The curve was installed like a roof shingle, according to Uhlir. Two crews started at the same point on the ground floor and worked in two directions, encircling each floor until they met on the other side, when they'd then move up one level. Workers installed the two-layer façade of rectangular glass panels like a bicycle's spoke and rim.
Some have compared the stacked, curved design to a wedding cake. Nine separate layers throughout the 121-story tower form different commercial and residential zones. That makes the glass on the outside—expensive low-iron glass used for increased transparency—a little like a wedding veil.
This type of construction has been tried before, but the Shanghai Tower is the first building where the gap between the layers will be inhabited, in this case by 10 acres of sky gardens. Landscaped with plants and trees as well as paths and small cafes, these parks and atriums will provide an escape for workers and residents.
"Think of that double skin space like a thermos, " says Uhlir. "On a cold day, it will insulate and warm the structure, while it'll cool the building in the summer. Plus, since you can just walk out to a garden, you reduce elevator usage. You don't have to always go down to the ground floor."
At its widest point, there will be 50 feet of green space between the walls; imagine looking out of an office on the 60th floor of a skyscraper and seeing parkland out your window. In a country where cities are becoming more and more dense, it seems like finding better ways to build up is a necessity.
Uhlir spent seven years as project manager for this construction site, overseeing thousands of workers; he's been in charge almost as long as a two-term president. When he visited in March, he could observe the surrounding landscape from the observation deck, looking down on the Huangpu River (as well as the tops of the other skyscrapers in the area). New buildings in the works, including the forthcoming Phoenix Towers in Wuhan, already has aspirations to stretch higher than the Shanghai Tower and become the tallest in China. Uhlir doesn't mind; he believes this building has more of a claim to inspiring future projects than simply being the tallest.
"There's always going to be a taller building," he says. "We tried to make the best building, the most sustainable and efficient. This concept of vertical urbanism here is unique. It sets a precedent that I think will be part of the legacy."