Block 21, a two-building development, is the fourth block of Amazon’s campus in the Denny Triangle.

The 28- and 8-story towers sit atop street-level retail and four levels of underground parking. A skybridge connects the two towers for efficient tenant movement throughout the workday. At 40 tons and 70 feet long, the bridge required two tower cranes to lift and maneuver it into place.

During preconstruction, Amazon made an exciting announcement; the company planned to donate space in the shorter of the two buildings to Mary’s Place — rent free, forever. Now open, Mary’s Place Family Center in The Regrade has its own entrance and elevators and provides private rooms for families and their pets.

Owner

Amazon

Owner Representative

Seneca Group

Architect

Graphite Design Group

Interiors Architect

SABArchitects, SABArchitects

Features

LEED Gold

Year Completed

December 2019

Project Stats

33

Elevators

13

Pieces of Stumpery

Mary's Place entrance
Mary’s Place Family Center in The Regrade has its own entrance and elevators and provides private rooms for families and their pets.

Approach Spotlight

Removing large stumps from Amazon Block 21 construction site

Diamonds in the Rough

Landscaping features a stumpery, with massive aging logs and tree stumps scattered about–13 in total. Salvaged or rescued from the chip mill, these seemingly unusable pieces of wood found a comfortable home at Block 21. GLY’s layout team conducted full Faro scans of each piece, which helped the landscape architect determine the best location and orientation of each stump and log before arriving on site.

Salvaged wood provided by Carter Evans Wood Concepts, Elma, WA.

Shaping the Future of Formwork

GLY partnered with EFCO to design and implement the Power Tower 100 [PT-100] on Block 21. This high-capacity, self-climbing formwork design features an 8-foot-wide working deck—a chief advantage that provides substantial increase in freedom of movement for both workers and materials. Iron workers can stage materials on the deck AND prefabricate reinforcing steel more efficiently, making the work safer and more productive than ever before.

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Amazon Block 21 during construction
First-of-kind crane at Amazon Block 21 construction site

A BIG First-of-its-Kind

Block 21 made use of the LCL700, the largest luffing-jib tower crane ever manufactured by Linden Comansa, and the first of its kind erected in the world. Its angled boom provides an efficient solution for jobsites in large and congested cities like Seattle, where reduced space creates radius challenges for traditional flat top tower cranes. It arrived in Seattle direct from Spain via boat.

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Sidewalk view of Amazon Block 21
Amazon Block 21 street view
Interior shot of Amazon Block 21
People working inside of Amazon Block 21
People working inside of Amazon Block 21
Architectural detail of Amazon Block 21
People walking down stairs inside of Amazon Block 21
Man working inside of Amazon Block 21
Mary's Place street view