Jeanne Gang discussing Chicago's Aqua Tower

JEANNE GANG: Up here on the third level, it's a giant roof garden, an amenities base for the people that live in the tower or staying in the hotel or people renting apartments. I think it's the second largest roof terrace in the entire city. We have 15 floors of hotel, and then the next floors, up into the 57th floor, are apartment units [music in], and then the final, all the way up to the 82nd floor, are condominiums.

When you look up at the building, you can see how each of the floor slabs are slightly different, and they kind of transform over the height of the building.

Concrete really has a lot more possibilities. It's not always used to its—its fullest. And one of the things about it is it can form to any shape. So we wanted to exploit that. Working directly with our owner and contractor, we came up with a way to change the formwork by using a flexible metal edge that would be able to be reused on each floor.

JAMES LOEWENBERG: Nothing more than a piece of steel they were able to bend to a radius, and then when they finished, it would snap back to straight. The importance of this is that there were about six miles of edge forming on this building. To be able to not waste this material, to put it up and then reuse it and keep on reusing it, was extremely important in a green building concept.

JEANNE GANG: We're always looking for a way to make it as low energy as possible [music out] and as compatible with the environment as possible in its particular climate. It's part of being—designing to be specific. A lot of times I don't really outline the points in the accreditation for a sustainable project when I'm talking about a project, because it's more inherent to its whole reason for being.

From here you can see how Chicago is dense right in its city center, but then the density really drops off as you go west. It was one of the more compelling things about doing a tall building for us. We have something in the order of 720 households that will be living in Aqua. And from this small footprint it's easy to go out and do your shopping [music in], be close to cultural institutions and to your place of work. If you compare that to a typical suburb, the carbon footprint is much larger because of the additional trips that everyone has to take in their car. So living in a high-rise is actually a much more sustainable pattern of development.

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