Q&A

Are there any innovative techniques needed to construct the building

Courtesy of the Downtown Seattle Association

Among the most innovative aspects was the installation of the transfer deck on the seventh floor. Seventeen massive steel trusses some weighing more than 80,000 pounds transfer the gravity loads from the concrete columns between the seventh floor and the roof to the central concrete building core, as well as to concrete columns near the perimeter of the base of the building. This was a unique approach to having two different structures of a condo tower sitting over a parking structure.

Also, the enclosures system being used on the Fifteen Twenty-One Second Avenue tower has been used only twice before in the greater Seattle area. This system is part of a German concrete forming system, PERI. The purpose is primarily to provide safety for the workers on the project. This system encloses three entire stories and climbs with the building. It encloses the current concrete floor being constructed and the two previously poured floors. Wind blowing out of the west across Elliott Bay can cause problems as we get further up the tower. Protection from the wind is extremely important during construction to prevent material from blowing off the building.

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What is the most difficult aspect of construction the schedule, budget or resources. What are you doing to solve it?

The biggest challenge is building on a tight downtown site with 100 percent exposure to the weather off of Elliot Bay.

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