Architects update pre-Columbian building method with modern tools and materials.Matter Design's latest installation, Round Room (on display at MIT's Keller Gallery last fall) was born of a "marriage" between two of the firm's ongoing interests, explained co-founder Brandon Clifford. First, Clifford and partner Wes McGee had long hoped to work with Autoclaved Aerated Concrete (AAC). Clifford, moreover, had been impressed during a trip to Cuzco by the Incan wedge method of masonry construction, in which precisely-carved stones are aligned on their front face, then backfilled with mortar. "This seemed like a tremendously rational way of building," he said. "Ever since then we had been wanting to do a project that translates that process into digital design." With Round Room, designed and fabricated in cooperation with Quarra Stone, Matter Design did just that. Though inspired by pre-Columbian building practices, the installation firmly situates the wedge method in the digital age. Clifford and McGee began by building a rough prototype, a six-component section resembling a half-dome. "We knew that we were going to build something that was round," said Clifford. "Not a sphere, but something that has slow changes in geometry." By focusing on curved spaces, the designers were already pushing the limits of the wedge method, historically limited to two-dimensional applications. With information gleaned from their prototyping session—including the general dimensions of individual units—they worked through a series of models in Grasshopper and Kangaroo, leaning on calculations developed for an earlier project, La Voûte de LeFevre. Clifford and McGee also visited Quarra Stone's Wisconsin facility. The trip "allowed us to get a feeling for where they were going to have problems with the geometry, and make changes," said McGee. "We were able to step in as consultant with respect to applying their tools." Using a water-fed robotic arm, Quarra Stone cut the AAC components—no simple feat. "One critical translation from the Incan technique was the fact that the front edge aligns, but the backwards taper allows for mortar to be packed in," explained McGee. "[The blocks] are machined on five sides." Round Room's components were then shipped to Cambridge and assembled on site by a team of students, including Myung Duk Chung, Sixto Cordero, Patrick Evan Little, Chris Martin, Dave Miranowski, David Moses, Alexis Sablone, and Luisel Mayas. (Austin Smith also assisted throughout the project; Simpson Gumpertz & Heger acted as structural consultants.) The installation team placed the blocks, used scrapers to remove any excess AAC from the front (interior) edge, then piped plaster into the wedge-shaped gap on the back (exterior) side. "Though it was a digital fabrication process, the assembly was quite a craft," observed Clifford. The collaboration with Quarra Stone was a first for Matter Design, which had both designed and built all of its earlier projects. "It was beneficial for us to understand the nuances of what they had to deal with on a daily basis," said Clifford. In fact, the relationship was so successful that Clifford and McGee are continuing it, with a fellowship that will send two researchers to the Wisconsin fabricators. "It's an area we're going to continue working in pretty heavily," said McGee. "It's an opportunity to interrogate this information exchange between designers and fabricators at a higher level."
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Installation investigates the future of facade design and fabrication.Unlike some student projects, AAC Textile-Block v2.0 was shaped by both practical and speculative concerns. In back-to-back courses at Pratt, undergraduates designed and fabricated a prototype section of a screen wall system made from autoclaved aerated concrete (AAC). Co-taught by Lawrence Blough and Ezra Ardolino, the design studio and prototyping seminar encouraged students to look beyond their computer screens to real-world constraints including block size and light and air circulation. "The idea was that we wanted to make something that has an application later on," said Blough. "It was more than a run-of-the-mill digital fabrication project," added Ardolino. "It was really a comprehensive fabrication project." Each student in the design studio created a scheme for a four-story facade comprising modules cut from standard 8-by-8-by-24-inch AAC bricks donated by Aercon AAC (additional funding was supplied by the Office of the Dean of the School of Architecture). All of the assemblies were required to be self-supporting; some students designed them to be structural or to act as a weather barrier as well. With help from structural engineer Robert Otani and facade consultant Erik Verboon, both of whom teach at Pratt, the students explored their designs using Rhino and wire-cut foam models before CNC-milling prototype wall assemblies from high-density foam. During the following semester, Blough and Ardolino's seminar moved into design-development. Again with Otani's assistance, the class modified one of the designs generated in the studio for fabrication. Among the issues the seminar students addressed was the balance between uniqueness and repetition in the final assembly. "Every block could have been unique, but then there's a question of whether or not it's more efficient to incorporate repetition," said Ardolino. "The students solved that one: they figured out how they could set up the system to be somewhat repetitive." The assembly as built contains 96 blocks of 20 different types. "The earlier stuff I'd done was trying to use as much off-the-shelf material as I could," said Blough. "Here we decided to really push it, and to take on more of the ideas of mass customization." Students milled the AAC modules from 8-by-8-by-12-inch half-bricks using a reconditioned auto-industry robot at Timbur, Ardolino's computer-aided design and fabrication studio. After considering their options, the team settled on an "in the round" strategy, in which the tool makes parallel passes around the Z axis of each block. The blocks were held to the table using custom-milled high-density urethane foam jigs. By working from the largest module to the smallest module, the students required only two jigs. "As the block got smaller, more and more of the jig got eaten away during milling—like a palimpsest," observed Ardolino. While Ardolino managed the off-site fabrication, Blough oversaw assembly in the School of Architecture lobby. Students volunteered their time between classes to lay courses of the milled blocks, using a high performance polyurethane construction adhesive in place of mortar. Slotted steel plates located two courses from the top and bottom of the 10-foot 8-inch by 4-foot prototype accept 1/4-inch rods, which also pass through channels milled into the faces of pairs of blocks. Thinner, staple-like steel rods provide horizontal reinforcement every fourth course. When the installation was up, the assembly team, realizing the floor was uneven, pushed it into plumb before shimming it and re-adjusting the tension on the rods. Though the installation is presently unsealed, Blough and Ardolino are investigating an epoxy-like coating that would protect the blocks from contact damage without obscuring the tool paths. "We like the tool paths—they make it look like dressed stone," said Blough. Though the multi-semester project was designed as a hands-on learning experience for the undergraduates, the professionals involved benefited as well. "I like the idea of this cross-pollination between what goes on in my office and in Ezra's office, and that we can then bring it back to the studio and really push it," said Blough. "It was really liberating for me to take it to this whole other level with Ezra and the students, because you have all these great minds working on it."