Concrete crews from James McHugh Construction Co. hauled up the final bucket of concrete to the top of Aqua, officially completing the 82nd floor of the structure, whose wavy concrete design has received international attention.

In keeping with tradition, an American flag flew atop the ceremonial bucket, which released concrete to pour the roof of the 874-foot tower. McHugh is the general contractor for the project and is self-performing the concrete work as well. Aqua's developer is Lakeshore East LLC, an affiliate of longtime McHugh client Magellan Development Group LLC. The design architect is Studio/Gang/Architects, headed by Jeanne Gang, with Loewenberg Architects the architect of record.

"Aqua represents a real step forward in what architects and contractors can do with concrete, from a design standpoint," said Dave Alexander, McHugh's senior vice president. "We feel this building marshals a whole new era of innovation in Chicago architecture and construction."

The design of the mixed-use tower already has received international attention for the undulating "waves" of concrete that will make up the balconies. Its exterior features a rippling effect that architect Jeanne Gang says mirrors the striated limestone outcroppings and formations that can be seen throughout the Great Lakes.

There is no repetition whatsoever in the ripples that make up the balconies, which range from zero to 12 feet deep, said Alexander. As a result, McHugh had to invent 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, while still adhering to an aggressive schedule that called for pouring a floor every four days. McHugh Concrete Superintendent Paul Treacy's solution for easily laid and reusable forming edges, using light-gauge steel and brackets, was so successful Treacy was named one of Engineering News-Record's Top 25 Newsmakers of 2008.

Treacy's system proved so successful that McHugh beat its own estimates, pouring a floor every three days rather than the proposed four days.

"Innovation comes from experience, and we're proud of our field teams' skill at creative thinking and problem-solving," Alexander said. "It sets McHugh's concrete services apart."

Aqua's wavy tower rises atop an eight-story pedestal base that will provide public spaces for a planned hotel - a lobby, restaurants, meeting spaces. The base also will house amenities for residents and will be topped by an incomparable 80,000-square-foot terrace with gardens, gazebos, pools, hot tubs, running track and fire pit. Six levels of parking are located below the raised street level of Columbus Drive.

The hotel portion of the Aqua will be housed in its first 18 floors, with apartments on floors 19 through 28, and condominiums from floors 29 through 82. The condominiums are 97 percent sold, according to Magellan, which also has launched leasing for Aqua's 474 apartments.

With the building topped out, trade teams will focus their attention on enclosing the building in its glass sheathing, and completing the interiors. Aqua's apartments will be ready for first residents to move in May 1 and the entire structure is slated for final completion in 2010.