• Tallest building in Seattle. While it was originally marketed as being the tallest building west of the Mississippi, it still holds the title for most floors in the United States outside New York City and Chicago. While both the J.P. Morgan Chase Building in Houston and Library Tower in L.A. are taller, neither has more floors with 75 and 73 respectively.
• The building was originally supposed to be 1,005 feet, however the FAA required a reduction in height for the project given it's proximity to the Seattle Tacoma International Airport, thus taking away Seattle's chance for a 1000 footer. The developer (Martin Selig) wanted to retain the same amount of leasing space in the tower, so instead of simply reducing the total number of floors, 6 inches was removed from each of the 72 office floors. The tower rises from a deep 120' excavation using conventional steel framing and three composite steel-concrete super-columns positioned on the center of each of the three faces. Each super-column was made from some of the first commercially available High Strength Concrete (fc' up to 9600 psi) and measures 8' x 12' at the base (tapering to 3' x 3' at the top) while resting on 48' square footings 14' thick. The slim profile of the tower also necessitated the use of visco-elastic dampers at the top to control wind and seismic motions.
• Following the construction of the Columbia Seafirst Tower (original name), public concern was raised about the potential for unchecked skyscraper development in Seattle and new measures were passed by the city in an effort to promote better development. This project may likely remain the tallest in Seattle for some time.
• A recent review of the tower's elevations revealed that, while the top of the penthouse is 1042.5' above sea level, the long-standing and much advertised height of 967' is incorrect. The tower has two points of entry separated by a 50' difference in elevation. At the main entry from 5th Avenue, the tower is 882'-6" from the fourth floor Plaza to the top of the penthouse roof. A second, less prominent entry permits access to the multi-level shopping arcade from 4th avenue and gives the tower a 932'-6" height to the same point. Likewise the tower can have either 73 or 76 floors depending on the point of reference used.
• In 1986, two antenna structures were approved by the FAA for the roof that would have reached 1,123 feet but were never built. They would have been 1,123 feet above ground level and 1,239 feet above mean sea level.
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