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May 15, 2015
Block 44 Amazon Phase IV
General contractor: GLY Construction
Primary designer: ZGF Architects
GLY Constructions’s Block 44 project added one five-story and one six-story office building totaling 395,700 square feet to Amazon.com’s global headquarters in South Lake Union.
The structure is post-tensioned concrete with drop beams and two glass-clad links connecting the buildings on three levels. A glass canopy transforms the outdoor courtyard to a woodland floor, with LED “fireflies” mimicking a forest at dusk. Sustainable features include rain gardens, a Pronto bike-share facility and an integrated streetcar stop.
Energy code updates, unorthodox geometry and difficult site conditions all lent unprecedented complexity to the project. Seattle’s new energy code required higher-performance envelope and mechanical systems, better articulation in the facade and more public amenities.
GLY played a key role in continually providing real-time cost updates and constructability options.
“What we got,” said Vulcan representative Jim Broadlick, “was the best value and the best design not to mention the best energy performance of any similar-sized building in our portfolio.”
Mastery of a truly complicated modeling environment also allowed GLY to deliver significant cost, quality and communication benefits, collaborating with the design team to model some of the project’s more complex geometries.
To meet the major challenge of excavation so near the water table, GLY designed a unique dewatering system that provided stability both during construction and for the life of the building, saving approximately $750,000 over a six-month period.
GLY constructed the building to float atop the water table with a waterproof concrete foundation to prevent water intrusion. Taking care of pedestrians, traffic and operating businesses was also a priority on this urban site. GLY provided monthly bulletins to area businesses and maintained proactive, cordial communications with neighbors throughout construction.
The project incurred 259,468 worker hours with no lost-time incidents.