Angles of shade

February 1st, 2016 / By: / Features

googleplex pic 1
Google’s headquarters, the Googleplex, uses SEFAR® Architecture’s TENARA Fabric to shade the central plaza of a recent campus expansion. The trellis creates a shade pattern, like sun passing through leaves of a tree. Photos: Sefar Architecture

Tech giant Google™ relies on old-school textiles to shed shade on its new campus expansion.

Google™ is known for its inventiveness, creativity and efficiency. It is no surprise that the unique Internet company continued that trend when it chose an industrial fabric solution for the outdoor area of its new campus expansion. The shaded area is used as a central plaza where employees can hold meetings, eat lunch, work away from their desks and relax. The installation at Google headquarters in Sunnyvale, Calif., known as the Googleplex, was designed to match the enthusiasm of the innovative and unique brand.

Light-diffusing triangles
The plaza features a large steel trellis that curves above the courtyard. To supply the right amount of shade, the trellis is outfitted with hundreds of fabric triangles. Charles Duvall of Duvall Design Inc. recommended fabric for the project for its unique light diffusing qualities.

“They wanted to shade the plaza, but they didn’t want to completely block the light out,” Duvall says. “They wanted the plaza to feel like light filtering through the leaves of a tree.” Fabric allowed just the right amount of shade to be created while still retaining the ambiance of California’s sunny weather.

After experimenting with HDPE and vinyl fabrics, Duvall and Google settled on a Teflon® material that would hold up well outdoors. “They immediately liked the Teflon when they saw it,” Duvall says. “It diffuses light very well and maintains a look of perfection even after several years. It has a very clean, nice look to it if it is designed properly and tensioned just right.”

The Teflon triangles are made of a white TENARA® Fabric, manufactured by Sefar Inc., Buffalo, N.Y. “The body of the fabric is the conventional 32-ounce, 40 percent architectural TENARA Fabric,” Duvall says. “The edge of each triangle is made of their exterior fabric with a very light Teflon edge cover protective coating on it. We couldn’t add too much weight to the fabric or it wouldn’t tension properly.”

According to Sefar, its fabrics are PVC-free, chemical resistant and inert to UV radiation. TENARA is a self-cleaning textile, as well. “I have installed other projects with this fabric that still look brand new after seven or eight years,” Duvall says. “Because it is an outdoor installation, I knew it had the potential to get dirty from sand and other airborne particles. The TENARA Fabric takes care of that problem and will keep the plaza looking nice for a long time.”

To ensure the fabric was in pristine condition, it was coated to protect it from being damaged during installation. Prior to installation, the TENARA Fabric is laminated on both sides with a protective layer. The layer allows the installation crew to handle the material without actually touching the surface of the fabric. The layers are then removed after installation, exposing the untouched surface.

Known for its ability to diffuse sunlight without negatively affecting light temperature or light transmission, TENARA Fabric was used to achieve the maximum amount of sun protection below the structure while retaining the ambiance of sunny California.
Known for its ability to diffuse sunlight without negatively affecting light temperature or light transmission, TENARA Fabric was used to achieve the maximum amount of sun protection below the structure while retaining the ambiance of sunny California.

Designing and installing the project

The steel trellis, designed by Valerio Dewalt Train Associates and engineered by Thornton Tomasetti, required nine distinct triangle shapes to fit within the project’s geometric shape. Each triangle had to be within 1.5 inches of the connector hubs when fully tensioned to maintain their shape. To accomplish the design goals of the plaza, Duvall experimented with different shapes and patterns of fabric membranes to find the best fit.

Several variables affected the shapes of the triangles. Because the trellis was curved and each piece of fabric needed to be properly tensioned, it took some experimenting to find the right combination of shapes and placements.

“We started the Google project by producing several mock-up triangles, which we tensioned on steel frames and shipped to the job site,” Duvall says. “After many experiments, we found an unusual curved shape, which was shallow in depth, yet allowed the membrane to tension evenly. This curve is somewhat flat across center and pointed at the corners of the triangle.” The curved edges of each triangle reduce the need for higher tension, requiring only 300 to 400 pounds of tension at each point.

In addition to the shape, Duvall had to consider load restraints. “I ended up treating the Teflon much like I would an HDPE fabric structure,” he says. “This helped me detail the curves and meet the engineering constraints. We couldn’t introduce more than 350 pounds of load to each point of each triangle. The frame couldn’t hold more than that. Fabricating the triangles this way allowed me to keep the load at the required level.”

To complete the installation and tensioning, Duvall developed 14 laser-cut stainless steel hubs. He bolted these onto threaded studs that were retrofitted onto the existing steel structure. “We welded 3/4-inch studs onto the frame at the attachment points so we could bolt the hubs onto them,” he says. “I went up in the lift and laid them out because they did not follow a conventional layout pattern. Because the structure is curved, I used turnbuckle components as a tensioning mechanism.”

Duvall installed stainless steel rings at the point of each triangle to connect to the hubs. “The edge of each triangle is made of a high-strength webbing with a Teflon UV cover to withstand tension and weathering,” he says. “I made sure to cover each edge well and add extra perforations. Then, I installed them by tensioning the rings at each point on the hubs.”

To get each triangle perfectly tensioned, Duvall had a trick up his sleeve. “There is one extra thing I did to make sure each triangle point was at the right angle to give the fabric the proper shape when under tension,” he says. “I actually used my 3-D printer to design a printed part that fits inside of the ring, changing the angle of the webbing on the triangle. It is a sort of spacer that allows the fabric to tension out perfectly. If I had just used the ring itself, the fabric pinches under tension and causes a wrinkle at the point.”

The final product resulted in a perfectly shaded space. The curved edges of each piece of fabric allow just enough sunlight to pass through, creating the desired effect of sunlight passing through the leaves of a tree. Google’s employees now have a comfortable outdoor space to collaborate and innovate on campus.

Jake Kulju is a freelance writer from Shafer, Minn.

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