After four years, three stages, and countless submissions, NASA’s 3D-Printed Habitat Challenge is winding to a close. The space agency’s competition to design a habitat that could be built on the Moon, Mars, or other planets made of local materials is reaching the final stage, and NASA has awarded $100,000 to be split among the three winners of the complete virtual construction stage. Eleven teams submitted proposals for the complete virtual construction stage, and on March 27, New York’s SEarch+ and Apis Cor took first place and received $33,954.11; the Rogers, Arkansas–based Team Zopherus took second and received $33,422.01; and New Haven, Connecticut’s Mars Incubator placed third and received $32,623.88. The complete virtual construction challenge asked teams to digitally realize their designs in the Martian environment using BIM, building off of an earlier stage in the competition that involved renderings. This time, competitors were judged on the habitat’s layout, programming, scalability, spatial efficiency, and constructability. Smaller 3D-printed models and videos were also produced. SEarch+ and Apis Cor proposed a series of tiered, rook-like towers printed from Martian regolith. The habitat’s hyperboloid shape, resembling a squeezed cylinder, arose naturally from the need to contain the building’s inward pressure; in a low-pressure environment, the greatest force exerted on a pressurized structure is a gas pushing outward (think of inflating a balloon). The habitat’s living areas and laboratories are connected but compartmentalized in case of an emergency thanks to a central service core. Each hexagonal window assembly was designed to be easily assembled in-situ and would contain redundant seals and pressure panes. Zopherus’s concept was simpler and lower to the ground, consisting of a series of latticed domes. The habitat(s) would be assembled by a lander, which would launch a series of autonomous robots to collect the raw materials. It would then mix the materials and print each hexagonal structure from the ground up, making “concrete” from Martian dirt, ice, and calcium oxide. The habitat and adjoining modules would be optimized to capture as much sunlight as possible, but would also include sliding panels to shield the windows for when the solar rays would be too intense. Mars Incubator chose to use a modular panel system for their proposal, utilizing regolith to create the panels’ plates. A central icosahedron would connect to several supplementary pods, and the entire structure would be elevated via a series of support struts, with the critical systems buried below. The primary living space would branch off and connect to a vestibule, multi-use space, and bio-generation pod where plants could be grown. The 3D-Printed Habitat Challenge is part of NASA’s Centennial Challenges program and is managed in part with Bradley University. The complete virtual construction stage was the fourth of five stages in the third phase, and the last leg of the competition will be held from May 1 through 4 at Bradley University in Peoria, Illinois, where teams will 3D print one-third scale versions of their habitats. The winners will split an $800,000 pot.
Posts tagged with "3D Printing":
“What if you could download and print a house for half the cost?” reads the lede for the Vulcan II, a 3D printer with a name suited for sci-fi space exploration, on the website of Austin-based company ICON. Now the company has put this claim to the test, building what it says is the first permitted 3D-printed home in the United States, unveiled during SXSW. Using its original Vulcan gantry-style 3D printer, the firm collaborated with global housing nonprofit New Story to build a 650-square-foot home, which features separate bedroom, living, bathroom, and kitchen areas. The home, called the Chicon House, was printed in under 24 hours and while this test cost around $10,000, the firm estimates that future single-story homes, which could be as large as 2,000 square feet, could be printed for thousands less, around $4,000–$6,500. According to New Story CEO Brett Hagler, there is a pressing need to “challenge traditional [building] methods” to combat housing insecurity and homelessness. He adds that “linear methods will never reach the over-a-billion people who need safe homes.” ICON hopes to leverage the technology to help combat global housing crises all while being more environmentally friendly, resilient, and affordable. The printers use a proprietary “Lavacrete” concrete composite, which is made of materials that can be easily sourced locally and has a compressive strength of 6,000 pounds per square inch. The material is designed to withstand extreme weather conditions to minimize the impact of natural disasters, according to the firm. Wood, metal, and other materials can then be added on for windows, roofs, and the like. The printer relies on an “automated material delivery system” aptly called Magma, which blends the Lavacrete with other additives and water stored in built-in reservoirs. The Lavacrete’s composition is custom-tuned to the particular conditions of each location, accounting for temperature, humidity, altitude, and other climatic features. While 3D printing has been used in a number of architectural experiments over the past few years, it is primarily used as a prefabrication tool, with parts printed offsite to be assembled later. ICON argues that printing a whole home at once with a gantry printer is faster and more reliable. Printing the whole home reportedly provides a continuous thermal envelope, high thermal mass, and extremely little waste. The printers, which are transported in a custom trailer, are designed to work in areas where there is limited access to water, electricity, and the infrastructure necessary for traditional construction techniques—although, at least currently, it seems that some more standard construction is needed to finish off the 3D printed walls and turn them into a home. The Vulcan II is operated by a tablet, has remote monitoring technology, and built-in lighting for building overnight. A specialized software suite helps convert CAD drawings into printable forms. ICON has also begun licensing its tech to others. Austin-based developer Cielo Property Group plans to start production of affordable housing in Austin this year using the Vulcan II, The Wall Street Journal reported.
Being able to translate research finds into practical applications on a construction site is never a sure thing, but having a lab-to-studio pipeline definitely helps. For Jenny Sabin, that means a close integration between her lab at the Cornell College of Architecture, Art, and Planning (AAP), and her eponymous studio in Ithaca, New York. Sabin wears three hats: A teacher with a focus on emerging technologies at Cornell, principal investigator of Cornell’s Sabin Design Lab, and principal of Jenny Sabin Studio. The overlap between the lab and the studio means that Sabin has an incubator for fundamental research that can that can be refined and integrated into real-world projects. When AN last toured the Sabin Design Lab, researchers were hard at work using robot arms for novel 3D printing solutions and were looking at sunflowers for inspiration for designing the next generation of photovoltaics. The projects stemming from fundamental research have been realized in projects ranging from the ethereal canopy over MoMA PS1’s courtyard in 2017 to a refinement of the studio’s woven forms for a traveling Peroni pop-up. Rather than directly referencing nature in the biomimetic sense, Sabin’s projects instead draw inspiration from, and converge with, natural processes and forms. Here are a few examples of what Sabin, her team, and collaborators are working on. PolyBrick Brick and tile have been standardized construction materials for hundreds of years, but Sabin Design Lab’s PolyBrick pushes nonstandard ceramics into the future. The first iteration of PolyBrick imagined an interlocking, component-based “brick” that could twist, turn, and eliminate the need for mortar. PolyBrick 1.0 used additive 3D printing to create hollow, fired, and glazed ceramic blocks that could one day be low-cost brick alternatives that would enable the creation of complex forms. PolyBrick 2.0 took the concept even further by emulating human bone growth, creating porous, curvilinear components that Sabin and her team of researchers and students hope to scale up to wall and pavilion size. PolyBrick 3.0 is even more advanced. The 3D-printed blocks contain microscopic divots and are glazed with DNA hydrogel; the polymer coating can react to a variety of situations. Imagine a bioengineered facade glaze that can change color based on air pollution levels or temperature changes, or a component “stamped” with a unique DNA profile for easy supply chain tracking. Responsive textiles As Sabin notes, knitting is an ancient craft, but one that laid the foundation for the digital age; the punch cards used in early computers were originally designed for looms. As material requirements evolve, so too must the material itself, and Jenny Sabin Studio has been experimenting with lightweight, cellular structures woven into self-supporting forms. Sabin’s most famous such installations are gossamer canopies of digitally knit, tubular structures that absorb, store, and re-emit sunlight at night to illuminate repurposed spool chairs. MoMA PS1’s Lumen for YAP 2017, House of Peroni’s Luster, and the 2016 Beauty-Cooper Hewitt Design Triennial installation PolyThread have all pushed textile science forward. As opposed to rigidly defined stonework or stalwart glass, woven architecture takes on ambiguous forms. As GSAPP’s Christoph Kumpusch pointed out while in conversation with Sabin at the House of Peroni opening in NYC last October, these tensile canopies proudly display their boundary conditions instead of hiding them like more traditional forms. The dangling, sometimes-expanded, sometimes-flaccid fabric cones extrude from the cells of the woven canopy and naturally delineate the programming of the area below. These stalactites create the feeling of wandering through a natural formation and encourage a playful, tactile exploration of the space. Kirigami Origami and kirigami (a form of paper folding that requires cutting) are traditional practices that, like other techniques previously mentioned, have seen a modern resurgence in everything from solar sails to airbags. The Sabin Lab has taken an interest in kirigami, particularly its ability to expand two-dimensional representations into three-dimensional forms. The lab’s transdisciplinary research has blended material science, architecture, and electrical engineering to create rapidly deployable, responsive, and scalable architecture that can unpack at a moment’s notice. Two projects, ColorFolds and UniFolds, were made possible by funding from the National Science Foundation. ColorFolds was realized as a canopy of tessellated “blossoms,” each made from polycarbonate panels covered in dichroic film. The modules open or close in response to the density of the crowd below, creating a shimmering exploration of structural color—3M’s dichroic film produces color by scattering and diffusing light through nanoscale structures rather than using pigments. Visitors below the ColorFolds installation were treated to chromatic, shifting displays of light as the flock-like piece rearranged itself. UniFolds reimagined the Unisphere in Queens’s Flushing Meadow Park as part of the Storefront for Art and Architecture show Souvenirs: New New York Icon, which asked architects and artists to produce objects inspired by New York City icons. The 140-foot-tall, 120-foot-diameter landmarked Unisphere was the centerpiece of the 1964 World’s Fair, and Sabin Design Lab’s UniFolds piece references the utopian aspirations of the sphere and domed architecture more broadly. By using holes, folds, and strategic cuts, Sabin Labs has envisioned a modular dome system that’s quick to unfold and can be replicated at any scale, which is part of the “Interact Locally, Fold Globally,” methodology used to guide both kirigami projects.
ETH Zürich’s high-tech showhome opened its doors this past week. The three-story DFAB HOUSE has been built on the NEST modular building platform, an Empa– and Eawag–led site of cutting-edge research and experimentation in architecture, engineering, and construction located in Dübendorf, Switzerland. The 2,150-square-foot house, a collaboration with university researchers and industry leaders, is designed to showcase robotics, 3-D printing, computational modeling, and other technologies and grapple with the interconnected issues of ecology, economy, and architecture. One of the central innovations is using robots that build onsite, rather than create prefabricated pieces in a factory. This In Situ Fabricator (IF) technology, an autonomous “context-aware mobile construction robot,” helps minimize waste and maximize safety during the construction process. To generate concrete geometries not permitted by conventional construction techniques, such as curvilinear shapes that minimize material use, researchers devised a Mesh Mould technology that was built with the aid of vision system–equipped robots. The robots fabricated a structure that acts as both formwork and structural support, a curved steel rebar mesh. The mesh is then filled with concrete, which it acts as a support to. In the DFAB HOUSE, the Mesh Mould is realized as a 39-foot wall, a main load-bearing component of the house, which is able to carry around 100 tons. Despite its complexity—it has 335 layers with over 20,000 welding points—the robot took just 125 hours to construct the mesh. https://youtu.be/ZeLEeY8yK2Y Cantilevered over the Mesh Mould is the so-called Smart Slab, a 3-D printed concrete formwork that supports the timber structure above. Many of the concrete forms in the home are built with what the researchers are calling Smart Dynamic Casting, an automated prefabrication technology. Robotic prefabrication is also used to make the Spatial Timber Assemblies that comprise the upper two levels of the home. The timber structure was devised as part of a collaboration between the university, Gramazio Kohler Research, and ERNE AG Holzbau, who used computational design to generate timber arrangements to fit into the larger structure. The timber assemblies also permit the creation of stiff structures that don’t require additional reinforcement. Applied onto the structure, the hyper-efficient facade is made of membranes of cables, translucent insulating Aerogel, and aluminum. In addition to all the new technology that went into building the DFAB HOUSE, it will also be a “smart home,” using what the researchers are calling the “digitalSTROM platform,” which includes “intelligent, multi-stage burglar protection, automated glare, and shading options, and the latest generation of networked, intelligent household appliances.” It also includes voice control for many of the home’s operations from turning on a kettle to operating blinds. Energy management is also a centerpiece of the home, with rooftop photovoltaic panels featuring a smart control system. Additionally, heat exchangers in the shower trays recover the warmth of shower water, and hot water from faucets is fed back into the boiler when it’s not in use. Not only does it conserve energy and water, it also prevents bacterial growth in the pipes. The radical use of technology in the DFAB HOUSE is also about optimization and efficiency: the home, with all its undulating formwork and translucent geometries, has been designed to demonstrate how new technology can develop and advance its own aesthetic language to make truly pleasing, compelling spaces. It will also be put to the test. Soon academic guests will be moving in and give life in the DFAB HOUSE a shot. For those who can’t make it to Switzerland, the project will also be presented during Swissnex in San Francisco.
3-D printing in architecture is growing—literally. Once limited to models and small pieces, the technology has recently been adapted to large-scale projects, like the world’s largest 3-D-printed concrete bridge in Shanghai, a stainless steel bridge in the Netherlands, and walls for U.S. military barracks. An Austin-based company has even begun selling plans for 3-D-printed houses, though thus far it seems like none have been built. However, as first reported in 2016, Branch Technology, is set to build what it claims is the “world’s first freeform 3-D-printed house.” The firm has already fabricated an array of projects with its giant 3-D printing armature: furniture, drone landing pads, an award-winning pavilion made in collaboration with SHoP architects for Design Miami in 2016, and what the company claims is the world's largest 3-D-printed structure. However, this would be the first building to be entirely made with the company's printing tech. The project got its start in 2016, when Branch Technology hosted its Freeform Home Design Challenge, inviting firms from around the world to propose a home to be made with its cellular fabrication technology. Out of the nearly 1,300 registrants, the winning entry, called Curve Appeal, came from WATG, and will be completed in partnership with various other firms and labs. The home, which has been designed with attention to the natural light available on the lot in Chattanooga, Tennessee, is intended to be net zero energy. It’s being built out of around 100 pieces of printed carbon-fiber-reinforced ABS thermoplastic, five-pound beams of which have been shown to bear as much as 3,600 pounds. Branch has been testing individual components and structural models, and creep testing the entire system to ensure that every part of the home comes together safely and securely. According to Branch’s David Goodloe, combining lightness with structural integrity defines the firm’s work, making its technology “fundamentally different” than other 3-D-printing construction companies. “Instead of asking 'How much can we 3-D print?'" Goodloe said, “we are asking ‘how little?’” Rather than trying to make components wholly of plastic or another printed material, Branch is leveraging freeform printing to produce what it refers to as a matrix, a lattice-like structure, that supports other materials. The printed form creates the structure to which materials like gypsum composite can be added to increase structural capacity, insulation, and energy efficiency. https://www.youtube.com/watch?v=pUIYAxh0k68 To build bigger, Branch has been scaling up. The company has recently doubled its capacity with four new printers, and is building a new factory to incorporate its advances in automation and speed. The goal, as with many firms and labs experimenting with 3-D printing in architecture and construction, is to bring greater customization to construction. Branch is aiming to complete its home later this year.
Brought to you with support fromIn 2015, the Norwegian Trekking Association announced a decision to construct two warming huts along the mountains that ring the town of Hammerfest to encourage hiking for both residents and tourists. The project brief called for a straightforward structure with a working wood-burning stove, an excellent view of the surrounding landscape, and suitability for the mountainous terrain. Norwegian-based practice SPINN Arkitekter and Britain’s Format Engineers answered this call with a cross-laminated timber shell with exterior Kebony panels.
Rhino Kangaroo and Grasshopper files, the team was able to craft a series of visual models for the project and a series of components that could be easily transported across the mountainous terrain for erection. "Snow simulations were performed to ensure that the entrance will remain snow-free as intended," said the design team. "Structural forces between the panels were determined to specify the correct type of screws and fasteners for the construction. Additionally, 3-D printing was used extensively to test out how the construction would fit together, and to test cladding options for the exterior." The rock-like cabins effectively consist of three layers: a 3-inch-thick CLT shell, a 1/8-inch-thick membrane, and a Kebony skin with a thickness measuring just under 1 inch. A system of frames and blocks are located between the exterior cladding and the CLT core. Two sets of 3.5-inch-thick screws are found on each tile edge, connecting to adjacent tiles and the overall structure. An initial prototype of the $100,000 cabin was constructed in a controlled warehouse environment to allow for the uninterrupted testing of component assembly. Over the course of four workdays, two groups of volunteers assembled the cabin's shell and cut the cladding panels. Following construction, the cabin was split in two and transported via flatbed truck to the site and craned into position for final assembly. Construction of the second cabin is currently in the works.One of the initial challenges of the project was to design a form that both blended in with the rugged setting and endure the harsh mountainous weather conditions. The first step in addressing these conditions called for the 3-D mapping of the two sites with a drone and photogrammetry software. With this territorial information plugged into
Printing concrete has long been looked to as a way to speed up construction times and cut waste, and more and more projects are being 3-D printed, from barracks to outdoor furniture. Now, the world’s largest 3-D-printed concrete pedestrian bridge has been completed in Shanghai, China, across the city’s Wisdom Bay pond. The 86-foot-long, 12-foot-wide bridge was designed and fabricated by a team from Tsinghua University School of Architecture's Zoina Land Joint Research Center for Digital Architecture (JCDA) led by professor Xu Weiguo. The curvaceous bridge, which mimics billowing fabric for the railings and uses pavers patterned after brain coral for the pedestrian portion, was inspired by the Anji Bridge in Zhaoxian, China. The bridge’s construction was a joint effort with the Shanghai Wisdom Bay Investment Management Company. This isn't the first time that a bridge has been robotically fabricated; see the stainless-steel bridge produced by MX3D for a canal in Amsterdam. However, this concrete bridge is more than twice the length of its steel counterpart. The bridge structure is composed of 44 separate hollow units, while the handrails were pieced together from 68 hollow blocks, all of them printed from a proprietary polyethylene fiber concrete mix meant to ensure a steady rate of flow while printing. First, a one-quarter-scale model of the bridge was printed to test the structure’s integrity. Then, over the course of 450 hours, two robotic arms printed the components for the full-size bridge. Vibration and strain-monitoring sensors have been embedded throughout the structure to track the bridge’s stability in real time and allow researchers to pinpoint where the greatest amount of stress is occurring.
Buzz around robotics in architecture has been steadily building for some time now, though it’s only in the last few years that the technology has seen much real-world action. However, robotic construction technology is seemingly one step closer to the commercial market as Australian company FBR has unveiled plans to bring its robotic bricklaying arm, Hadrian X, out of the testing facility and into the real world. Earlier versions of the Hadrian, which shares the name of the Roman emperor perhaps most famous for his namesake wall that stretched across what is now the United Kingdom, had successfully created buildings in closed environments as early as 2015. This past November, the latest version built a nearly 2,000-square-foot, three-bed, two-bath home in a lab in under three days. After this success, FBR is attempting to take the robot out into the wild, with plans to build ten homes this year. Being billed as “the world’s only fully automated, end-to-end bricklaying solution,” the 100-foot, truck-mounted arm is able to lay as many as 1,000 bricks in a single hour without changing position. It interprets CAD files, calculating required materials on its own, before setting out to make the digital plans a reality. According to a blog post from January 11, FBR has begun preparatory work, including adding additional sensing equipment for weather conditions and the like, for the Hadrian X’s first outdoor build, a three-bedroom home that will be even more complex than the structure built in the last indoor test. Rather than aiming for speed, FBR sees this first build as a chance to “gather as much intel as possible,” in order to make any necessary engineering adjustments and to prepare to launch its autonomous bricklayer for commercial construction use—a business in which the company says there is an “immense” demand for automation. Hoping to make building safer, faster, and less wasteful, CEO Mike Pivac believes that there’s “massive potential for [autonomous building] technology...to shape the way the construction industry operates in the future.”
Concrete is a ubiquitous building material, applied to the bulk of contemporary construction projects. While the sedimentary aggregate is commonly used due to its impressive compressive strength, it remains a brittle material subject to damage or failure during extreme environmental events such as earthquakes. In response to this inherent weakness, a team of researchers based out of Purdue University’s Lyles School of Civil Engineering comprising professors Jan Olek, Pablo Zavattieri, Jeffrey Youngblood, and Ph.D. candidate Mohamadreza Moini has developed a 3-D-printed cement paste that actually gains strength when placed under pressure. The project, initiated in August 2016 with funding from the National Science Foundation, looked towards the natural durability and flexibility of arthropod shells. “The exoskeletons of arthropods have crack propagation and toughening mechanisms,” said Pablo Zavattieri, both of which can be reproduced “in 3-D-printed cement paste.” For the prototype, the research team cycled through a number of geometric configurations, including compliant, honeycomb, auxetic, and Bouligand designs. Each of these formats responds to external pressures differently; a compliant design acts as a spring under stress while the Bouligand boosts crack resistance. To assess the structural qualities of each prototype during and following testing, the team relied on micro-CT scanners. Through the use of this tool, the team was able to identify weaknesses present within the 3-D-printed objects, improving upon them with successive prototypes. What are the implications of the Purdue team’s 3-D-printed cement paste? In boosting the flexibility of concrete construction, the cement paste could add an extra factor of safety for the brittle material within conditions of environmental extremes, dampening the impact of momentary shocks. Admittedly, Zavattieri noted that the “minimum amount of material was used to prove the hypothesis.” However, there is no significant engineering hurdle in scaling up the technology to a potentially full-scale prototype and its ultimate application in architectural design.
The MIT-based Mediated Matter Group, founded by architect and designer Neri Oxman, is well known for its groundbreaking explorations at the nexus of 3-D printing, design, and what Oxman refers to as "material ecology," a term that covers projects ranging from a CNC-fabricated scaffold coiled with silk thread produced by 6,500 silkworms to a solid wooden chaise adorned with 3-D printed, multi-colored cells. Now, the group has released footage of their latest project involving a swarm of robots, dubbed Fiberbots, capable of rapidly fabricating freestanding fiber-reinforced tubes. Over the course of 12 hours, the Fiberbots autonomously produced a series of approximately-15-foot fiber structures. The 16 tubes are four inches in diameter, each using an estimated 1.2 miles of fiberglass thread. In total, over 80 miles of fiberglass were spun for the entire installation. “Fibreglass can provide energy-efficient, green, sustainable solutions for building enclosures,” said Neri Oxman in a statement to Dezeen. “It has relatively low embodied energy due to its composition and can be shaped to carry loads in multiple directions.” Mediated Matter Group tested their new device in Cambridge, Massachusetts, in an outdoor environment to gauge the Fiberbot’s durability. The design team fastened a series of external monitors to the robots to allow for a real-time response to external stimuli that adjusted fabrication variables to swings in temperature and or wind speed. The body of each Fiberbot is identical, consisting of electronics and a software drive enclosed in an inflatable silicone membrane. The Fiberbot is topped by a curved robotic arm that continuously wraps a mixture of fiberglass thread and photocurable resin around the existing structure. The materials for the structure are located at the base of the tubular forms and are siphoned upwards towards the robot's nozzle. Each robot navigates the freestanding structure through the compression and inflation of its surrounding silicone membrane. The membrane expands while the robot fabricates a new fiberglass segment, and subsequently retreats within the tube as that segment solidifies. This process follows a pre-programmed trajectory to ensure that none of the tubes inadvertently collide. According to the Architect Magazine, Mediated Matter Group is currently researching how to scale up their technique into full-scale architectural prototypes. However, there are significant hurdles to overcome in developing the fiberglass forms into load-bearing, interlocking frames.
A research team within the U.S. Army Corps of Engineers recently 3-D printed full-scale concrete walls in an effort to create quick-to-assemble barracks for field housing, according to Engineering News Record. The project, named Automated Construction of Expeditionary Structures (ACES), aims to engineer structurally efficient and safe concrete barracks with precast roofs and 3-D-printed walls. In their latest tests, they were able to produce 9.5-foot-tall reinforced concrete walls for 32-foot by 16-foot barracks, made from about 25 cubic yards of concrete. The next phase of the testing will tackle printing concrete roof beams. Backed by the U.S. Marine Corps, Caterpillar Inc., NASA’s Marshall Space Flight Center, and the Kennedy Space Center, ACES is pushing the boundaries of military on-site construction using as little money and manpower as possible. The project has undergone two years of testing with structural engineering experts from the Chicago office of Skidmore, Owings & Merrill, who had previous experience working in 3-D printing through a project with the U.S. Department of Energy. After several iterations, the group concluded that construction time on such structures could shrink to a single day as opposed to five days, the average amount of time it takes to build wood-framed barracks. Printing concrete barracks would also eliminate the need to ship construction materials for conventional barracks by instead using local concrete from wherever the build-out would occur. For this prototype, ACES spent $6,000 and in addition, found out that it would take just three trained crew members per shift for three continuous printing sessions to build the barracks. Though exhausting, the process is even less labor intensive than basic barrack construction. While 3-D-printed building technology is looking more viable every day, it's not perfect yet. According to ENR, SOM said that pre-testing the performance of the concrete is imperative and that the printing process must not be interrupted to ensure overall structural efficiency. Cracks from shrinkage can occur on long, straight walls as well, so ACES employed a chevron design that undulates, changing direction every two feet. ACES will do further testing over the next month to refine the technology and the construction process. They expect to be done with the project's precast concrete roof in September and will then issue a report with design guidelines. During 2019, the group hopes to build four or five pilot machines for Marine Corps units to use in the field for additional evaluation.
A research team led by Jamin Dillenburger, an assistant professor at ETH Zurich, has recently produced and installed a concrete ceiling shaped by 3D-printed sand formwork. Dubbed the “Smart Slab,” the 1000 square-foot ceiling is significantly lighter and thinner than comparable concrete ceilings. The concrete slab is a component of ETH Zurich’s ongoing DFAB House project. The DFAB House is a load-bearing timber module prefabricated by robots. According to ETH Zurich, Dillenburger’s research group “developed a new software to fabricate the formwork elements, which is able to record and coordinate all parameters relevant to production.” In effect, the design of the ceiling is the product of the team-created software rather than analog design or planning. Following the design and digital testing phase of structural elements, the fabrication data was exported for the creation of 11 pallet-sized, 3D-printed sand formworks. After fabrication, each segment was cleared of sand particles and prepared for concrete spraying. The spray consisted of several layers of glass-fiber reinforced concrete. At its thinnest point, the concrete shell is less than one inch thick. After hardening for two weeks, the 11 concrete segments were joined to create the approximately 15-ton floor plate. While the underbelly’s contours were formed by 3D-printed sand casts, the ribbed grid above was shaped by CNC laser-cut timber formwork. The load-bearing ribs, resulting from timber formwork, were outfitted with a series of tubes for the insertion of steel cables both horizontally and vertically. These post-tensioned ribs carry the principal load of the “Smart Slab.” In placing the principal load above the concrete shell, the research team was able to insert complex geometric features below. The “Smart Slab” is not ETH Zurich’s first execution of an ultrathin concrete unit. Earlier this year, the university fabricated an undulating, two-inch thick roofing unit for a new live-work space in Zurich.