Lease Crutcher Lewis overcomes hurdles to complete 505 First Avenue Building three months early
Seattle – Lease Crutcher Lewis has completed the 292,000 square foot 505 First Avenue South office building in Pioneer Square. The building, originally intended to house Starbucks’ offices, was redesigned during construction to optimize it as top-quality leasable space. Once the redesign was complete, Lewis fast tracked the project and completed it three months ahead of schedule.
Construction was well underway when Starbucks chose not to occupy the building, and to instead redesign it for potential tenants. As project architect, NBBJ led the redesign, with GCI designing the main lobby interior. The lobby needed to accommodate the needs of multiple tenants rather than one, and ended with a showpiece design that includes a 60-foot video wall. A planned feature stair through the office levels was deleted to add new floor area, and skylights were redesigned. Some connecting elements between 505 First and the adjoining 83 King Building were deleted, but the integration of fire sprinklers, fire alarm, emergency power and the building control system were retained in the new design. Since Starbucks also chose to vacate 83 King, new scope was added there, including a reroof of the historic building.
Construction challenges were abundant, beginning with the excavation for the 400-car garage. Excavation extended 42 feet below grade but the water table is less than seven feet below grade. After studying options, the team chose a cutter soil mix (CSM) subterranean wall – an innovative approach new to Seattle. It was the least costly, and allowed for the drilling precision and vibration control necessary to protect the century-old sewers and structures around the site. The wall, a mixture of cement, bentonite, and soil plus soldier piles, formed nearly-watertight shoring during construction.
Bordered by historical buildings – Triangle Tavern and 83 King Street – as well as the heavily traveled Viaduct ramp and First Avenue, the shoring was complex. It required 450 tie backs that were coordinated using building information modeling (BIM) to avoid conflicts with soldier piles belonging to adjacent buildings. Layout was also crucial to detail the location of 370 tie-down anchors that had to meet exacting clearance requirements and to avoid conflicts. At one point, the soil mixing, soldier piles, auger cast piles and micro piles were being installed simultaneously.
Two historic facades from the "Annex" wing of 83 King were incorporated into the building. One facade along First Avenue was preserved in place with steel bracing, requiring intricate shoring, underpinning, and excavation plans. The facade along Railroad Way was taken apart and reconstructed (with permission from the Pioneer Square Preservation Board), which was aided by dozens of photographs and as-built documents created by the team in advance of the deconstruction.
Construction of the all-new facade portions was simplified by Lewis building a full-size wall section mockup in advance. This was a major exercise, but paid off many times over by helping identify conflicts and solutions early on, and by allowing Lewis to show issues to NBBJ and the subcontractors better than thousands of words could ever do.
The result is a beautiful and economically viable addition to Pioneer Square, with 280,000 square feet of office space and 12,000 square feet of retail. The sustainable project is in line to win LEED Silver. The pending removal of the Viaduct will open up waterfront views to the west and greatly enhance the look of the building.
In addition to Starbucks, NBBJ, GCI, and Lease Crutcher Lewis, the team included The Seneca Real Estate Group (Owner Representative), Martin Smith (Property Manager), Coughlin Porter Lundeen (Structural & Civil Engineer), Hart Crowser (Geotech Engineer), Condon-Johnson (Shoring Design-Builder), Holaday-Parks (Mechanical / Plumbing Design-Builder), and Nelson Electric (Electrical & Lighting Design-Builder).
About Lease Crutcher Lewis
Lease Crutcher Lewis has been a leading Northwest general contractor since 1886, and has been based in Seattle since 1939. Lewis is active in numerous project types, including office, medical, biotech, education, retail, hotel, historic renovation, and others. Common threads for its work include an integrated approach to working with customers and design partners, a focus on optimal use of technologies such as BIM, and performing a large percentage of its work with its own craftspeople.