Precast Concrete Wall Panels Mimic Stacks of BooksThe three-dimensional glass-fiber-reinforced concrete walls in the lobby of Amazon.com's new office symbolize the company's booming Internet book business
Project submitted by Steve Silberman, Absolute ConcreteWorks, Seattle, Wash.
The three-dimensional GFRC wall panels are the focal point of the main lobby and first-floor corridor of Amazon.com's corporate headquarters, rising 28 feet high in the center lobby. (Photo credit: Roger Turk, Northlight Photography, Seattle).
All the panels were cast in a natural-gray portland cement. The "bookmarks," inserted at random, are made of glass..
Sixteen different wall panel molds were needed to achieve the tight tolerances required.
The wall panels after removal from the molds
Design challengeAlthough you can't read the books lining the walls, from floor to ceiling, in the first-floor lobby of Amazon.com's newest building in downtown Seattle, they still tell the story behind the Internet retailing giant's phenomenal success. These books are actually three-dimensional replications in eco-friendly precast concrete, and were recently installed as part of a LEED Gold building project. Although Callison, the project architect, initially wanted to use standard reinforced concrete panels to represent the rows and rows of books, they determined that the weight would be a problem and the cost of installing the panels would be outside the scope of the project budget.
The solutionSteve Silberman of Absolute ConcreteWorks (ACW), the wall panel fabricator, worked with Kurt Nelson at Callison, the interior project architect, to come up with a way to reduce the weight of the wall panels and the cost of fabrication and installation. "I advised him that glass-fiber-reinforced concrete would be the best way to go," says Silberman, who used ACW's SoundCrete GFRC mix to make the panels, reducing the weight by at least 25%. The lighter weight made the panels easier to maneuver and faster to install, he adds, reducing labor requirements and the overall cost of installation.
Also of extreme importance was maintaining tight tolerances between panels, both on the flat faces and the panels that wrapped around corners, while making the pattern seem random. "This required the use of 16 different mold variations, the majority of which were made of fiberglass and others cut out of wood using CNC machines," says Silberman. "In our shop, Chris Karlik used his skills as a fourth-generation sculptor and mold maker to build the fiberglass forms to the tight tolerances required, while Mark Venezia oversaw the mix design and casting process."
ACW worked with the general contractor on the project and a structural engineer to design an attachment system for installing the panels. They ended up using a Z-clip system to accommodate stainless steel inserts that were embedded in the GFRC panels during casting. The finished panels, 1,500 square feet in all, were then delivered to the jobsite from ACW's shop on pallets, after being carefully banded and shrink wrapped.
Applications for precast concrete wall panelsVertical concrete panels are not new to ACW, according to Silberman, who says that other popular applications include wall panels for use above fireplaces, wainscoting, and shower walls. "In showers, the concrete wall panels are easier to maintain because there are no grout lines. The panels can also be custom templated to accommodate plumbing fixtures," says Silberman. To give the shower walls a waterproof finish and make them easier to maintain, the panels are coated with a penetrating sealer.
Project teamGFRC wall panel fabricator
Absolute ConcreteWorks LLC / Seattle, Wash.
GLY Construction Project Manager
Callison / Seattle, Wash.
Gly Construction / Bellvue, Wash.
Wall panel structural engineer
B2 Structural Engineers / Seattle, Wash.
Northlight Photography Seattle (Roger Turk)
Related resources:Glass Fiber Reinforced Concrete: How to use GFRC for better decorative panels and countertops
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