The Rainier Square Tower (59-story, 850 ft/ 259 m tall) in downtown Seattle, is getting off the ground, with its completion scheduled for early 2020.
Traditionally, a rebar-reinforced concrete core has been the preferred method of construction for Seattle’s towers. These cores are very good at bracing against wind and seismic loads. The construction process is slow, though: three to four days per floor, with the steel framing for each floor dependent on completion of the concrete work.
For Rainier Square Tower, a new steel plate & concrete composite fill design for its high-rise core is used. It has been developed by Magnusson Klemencic Associates (MKA) over many years. The system uses two steel plates connected by steel spacing ties, and then the cavity between the plates is filled with high-strength concrete. An added boon is that this method is expected to reduce traditional construction time by 30% or more.
Here’s the current snapshot of the Rainier Square Tower construction cam, showing the carefully excavated hole and the first steel plates for the tower’s foundation and core. At the top right is the 1970s 40-story Rainier Tower, holding its own on its 12-story pedestal. Measurements show that that so far so good: everything on that side is solid.I took this picture on Tuesday, showing another U-shaped, hollow section of two sets of connected steel plates, being put into place. The new Rainier Square Tower (59 floors) will be right next to the existing Rainier Tower (40 floors).Left: A rendering of the completed Rainier Square Tower, designed by NBBJ – an American architecture, planning and design firm that was founded in Seattle in 1943, and today has offices around the world. The curve towards its top allows it to be built next to architect Minoru Yamasaki’s 1970’s Rainier Tower, without completely obscuring it. Right: The filled steel plate core will go up all the way to the top, making for a very resilient structure. [Rainier Square Tower rendering courtesy of Wright Runstad & Company; conceptual graphic of steel core courtesy of Magnusson Klemencic Associates].
