Aqua Tower tops out

By Richard High12 March 2010

Chicago’s 249.7 m-high Aqua Tower topped out this month (April 2009). Image: Studio/Gang/Architects.

Chicago’s 249.7 m-high Aqua Tower topped out this month (April 2009). Image: Studio/Gang/Architects.

Chicago's Aqua Tower has topped out with construction crews from James McHugh Construction hauling up the final bucket of concrete earlier today (17 April).

In keeping with tradition, an American flag was flown on top of the ceremonial bucket, which was lifted by crane and released concrete to make the final pour on the roof of the 874 ft (249.7 m) high tower.

The 89-storey residential and hotel Aqua Tower's exterior features a rippling effect that mirrors the striated limestone outcrops and formations seen throughout the Great Lakes region.

There is no repetition in the ripples that form its balconies, which range from 0 to 12 ft (3.66 m) deep. As a result, McHugh's concrete superintendent Paul Treacy invented a way to custom-build all the forms to pour the concrete for the balconies, with every one unique and the shape of each edge custom-built.

The system had to allow McHugh to pour a floor every four days, but was so successful McHugh poured one every three days.

Record tower

At 249.7 m-high Aqua is the third-tallest building in the world designed by a woman, only the two Emirates Towers in Dubai, which were designed by Hazel Wong, are higher.

It is currently the 40th tallest building in the US and the 5th tallest tower completed in 2009.

Drilling on the first of more than 300 foundation caissons started on March 12, 2007 and it is constructed on top of an 8-storey podium that will house public spaces for a planned hotel and an 80000 ft2 terrace with gardens and a running track. There are six levels of parking located below the raised street level of Columbus Drive.

McHugh is the general contractor for the project and is carrying out the concrete work as well.

The design architect is Studio/Gang/Architects, headed by Jeanne Gang, with Loewenberg Architects the architect of record.

Magnusson Klemencic Associates served as Aqua's structural engineers.

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