Photo by Moris Moreno; courtesy of MG2

The pool, located 440 ft above ground, required the installation of a temporary structure—made up of castellated steel beams that were attached on one end to the building’s concrete core—to support formwork for its concrete body. “[They] were cantilevered by about 40 feet beyond the footprint of the tower,” says Jooyeol Oh, principal at MG2, the project’s executive architect. The beams were also connected to the front edge of the floor slab below, reinforced by three concrete floor slabs connected with temporary steel posts. The total length of these beams could run up to 85 ft long. Nearly two years of close collaboration were required to deliver the pool.

The building contains over 50 unique unit types, reducing the level of repeatability typically relied upon in tower projects.
Photo by Moris Moreno; courtesy of MG2

The scope included excavating Seattle’s deepest publicly accessible basement—eight floors deep with an additional 12-ft-deep mat slab. “Given the extreme excavation depth, limited site footprint and lot-line construction, a telescopic dipper was required to remove spoils efficiently,” says Mitch Zutter, project executive at Build Group.

To facilitate close collaboration, the team co-located offices. “Questions were resolved through in-person discussions rather than phone tag or extended email exchanges,” says Zutter. Oh concurs, citing as an example an issue with the 7th floor garden: “Since the architect was working onsite and participated in the impromptu discussion, an alternative solution was found much faster than in a typical RFI process. In fact, an RFI was issued simply as confirmation of the solution.”