Seattle— DBM Contractors Inc. is installing temporary excavation support for the below-ground parking garage at the Four Seasons Hotel under construction in downtown Seattle.

Special logistics include extremely tight access working along a major downtown arterial as well as integrating installation within the existing building to ensure the safety of First Avenue during building demolition.

The project requires installing 82 piles up to 89 feet deep; 223 tieback anchors up to 94 feet long, the top two rows from within the existing parking garage prior to demolition. The project covers just over 21,000 square feet of retained excavation face. Additionally 13 drilled piers, with a diameter of 4 feet and up to 72 feet deep, were installed as part of the new structure's foundation. General contractor on the project is Lease Crutcher Lewis. Structural engineer is Magnusson Klemencic Associates and the Geotechnical engineer is Shannon & Wilson.