Kenneth Tracy and Christine Yogiaman of yo_cy applied research from working with concrete to dispel the singular material tendency of digital fabrication.
Out of 68 submissions from 17 countries across four continents, the winning proposal of Tex-Fab’s APPLIED: Research through Fabrication competition at the University of Texas at Arlington came from Kenneth Tracy and Christine Yogiaman of yo_cy, a collaborative design studio that utilizes digital techniques for maximum design effect. Their winning idea is called Cast Thicket, a study in tensile concrete that takes off in variations like a game of Cat’s Cradle.
“The initial idea was to apply our research toward the competition,” said Tracy. The designers used their experience with an Indonesian material called bilik—a soft, woven bamboo mat typically used as a vertical divider—that helped form a fabric, cast concrete wall for a residential project in Southeast Asia. “We wanted to make something from a construction material that is normally very heavy looking [and] invert the stereotype of the carved aesthetics of concrete to create something that is lacy, thin, and delicate.”
While most concrete molds utilize steel or plywood casing, Tracy and Yogiaman opted for a .03-inch thick plastic that deforms once filled to create a unique textural detail not unlike the bamboo Indonesian mats. To design the columns and create variations in their diameter, yo_cy used Kangaroo. This plugin for Grasshopper simulates the surface shrinking and swelling typical of concrete, giving the designers a good idea of how their project would look when completed. The duo hopes the successful use of a thin, recyclable plastic mold could reduce the environmental impact of site-cast construction in the future.
Cast Thicket is composed of 44 struts that intersect at several nodes. The struts are reinforced with a cage flat steel and thin steel tubes spanning between a wooden pallet base and capping sheet. Within the nodes are moments of tension, where the lacy network of lines are gathered together. “You can see this in Kangaroo like a set of strings, like a Cat’s Cradle game,” explained Tracy. “The idea is that a system can deal with contingencies of a complex architectural form. Rather than make a space with the piece, we wanted to create a set of conditions, like a network that proved its own variability and flexibility.”
The designers wanted a lightly colored material, something stronger than traditional cement that would pick up light and shadow, thus highlighting surface details. They chose an aggregate of materials void of dark tones, including limestone powder, white fiber reinforcement, Poraver glass beads for weight reduction, and metakaolin—a common material in porcelain. A superplasticizer that reduces viscosity binds the mixture.
“It helps to see the way materials behave in construction, but physical testing is critical,” said Tracy of Cast Thicket’s ability to bear weight. “[With this project] we are reacting to the singular material tendency of digital fabrication and [we have shown that] we can use the computer to coordinate different methods of making a material, and simulate that on a smaller scale.”