skip to Main Content

Seattle, Washington


Rainier Square in downtown Seattle encompasses almost an entire city block, and currently contains the iconic Rainier Tower, designed by Minoru Yamasaki- architect of the World Trade Center. To complete Rainier Square, a 58-story mixed-use skyscraper is underway directly adjacent to the 40-year-old Rainer Tower. At 850 feet tall, this new structure will be the second tallest building in Seattle.

Foundation excavation will reach 87 feet below grade of the Rainier Tower foundation and will have 85,000 square feet of soldier beam shoring and over 135-foot long tiebacks. Soil conditions consist of 15 feet of fill over 30 feet of silty sand and 50 to 60 feet of clay with slickenside, which is characteristic due to the nearby Seattle fault zone and glacial till. Where the excavation is deepest, a secant pile shoring wall with tiebacks has been chosen to mitigate any settlement issues of the nearby Rainier Tower.

To learn more about this project, please contact Brittan Ranstrom at

Back To Top