May 18, 2015

Architectural/Decorative Concrete

Photo courtesy of ZGF Architects

A concrete pedestrian breezeway runs between the two buildings at Block 44.

Block 44 Amazon (phase six)

Location: Seattle

Block 44 consists of five- and six-story buildings with 380,700 square feet of office space and 15,000 square feet of retail over subterranean parking at the corner of Westlake and Mercer. The buildings are linked by a glass canopy over a concrete pedestrian breezeway running between them.

A rooftop terrace for tenants has pathways that interweave with landscaping.

For the public, open space surrounding the buildings can be found at ground level. The breezeway, or crossblock, is bookended by water features, outdoor seating and landscaping. The glass canopy six stories above grade provides weather protection and is a public art installation that transforms the courtyard below to a wooded floor as light shines through the glass. When natural light is low, 100 twinkling LED “fireflies” are choreographed to mimic a forest at dusk.

With an average 10-foot elevation change from one end of the crossblock to the other, nothing was parallel or square. The contractor precisely modeled the complicated geometry, including multiple elevation points, to ensure smooth concrete paving throughout.

Walls for the water features varied from 6 to 8 feet tall, with a finished walking slab on top. Each piece is essentially a waterproof concrete bathtub invisible below grade.

Finally, the contractor removed and replaced aggregate by hand before the curing process to achieve the right degree of exposure.

Other Stories:

• Record mat pours: Lots of concrete and 600 workers
  
• Sustainable Merit
  
• Concrete Paving
  
• Cast-In-Place Concrete (tie)
  
• Cast-In-Place Concrete (tie)
  
• Pervious Concrete
  
• Public Works: Infrastructure
  
• Public Works: Bridges
  
• Tilt-Up Structures
  
• GRAND AWARD
  Public Works: Renovation • Special Applications: Technical Merit
  
• Special Applications: Artistic Merit