Not long ago, 3D printing in construction was the realm of small-scale hobbyists and design competitions. Those days are quickly fading from view.
In June, for example, Eindhoven University of Technology announced Project Milestone, a plan to 3D print a series of obeliscal concrete homes designed by Houben & Van Mierlo Architecten—an endeavor described by the university as “the world’s first commercial housing project based on 3D printing.” And housing is just one aspect of a market that one industry report predicts will grow from $70 million in 2017 to $40 billion by 2027.
The construction industry has turned to 3D printing to realize complex shapes, build in dangerous or remote areas, and reduce material waste and onsite construction costs, among other benefits. As the software and equipment for 3D printing improves, legacy construction companies and startups alike are recognizing its potential for real-world fabrication. Here are a few use cases that are shaking up the industry.
Case 1: Bridges
For a long time, the size of a 3D-printed project was limited by the size of the printer. But the Dutch firm MX3D (tag line: “We Speak Robot”) is using industrial six-axis robots, proprietary software, and welding machines that deposit stainless steel from thin, molten wire to build a 40-foot-long smart pedestrian bridge spanning the Oudezijds Achterburgwal, one of the oldest canals in Amsterdam, dug in 1367.
Designed by Joris Laarman Lab in collaboration with Arup and supported by Autodesk, ArcellorMittal, Heijmans, Lenovo, and other partners, the bridge is undergoing structural validation testing at Imperial College London. “Validating a bridge as novel and experimental like this one requires a method that is completely new,” says Tim Geurtjens, co-founder and former chief technical officer at MX3D. “The modern traditional way is to do everything digitally. You make a design, test it with a software package, and put a stamp on it according to regulations. But there is quite a bit unknown about material properties of printed forms.” MX3D aims to trial the load capacity of a physical model at various points, such as the handrails, to make precise adjustments.
The bridge will be shown at Dutch Design Week in October and, if all goes as planned, installed in Amsterdam in 2019. A sensor network on the bridge, developed by the Alan Turing Institute, will collect real-time strain, vibration, displacement, and environmental data. The Amsterdam Institute for Metropolitan Solutions will connect this data to the city’s smart infrastructure grid. But, Geurtjens says, “3D printing is not all about efficiency. The joy of living, aesthetic pleasure, we think are also really important. It’s not just for commercial sake; it’s also to make what you want to make because it’s possible.”
Case 2: Homes
For 3D-printed homes, construction companies are rushing to claim superlatives: the largest, the most quickly built, the cheapest, the most materially efficient. Designs are emerging from all corners of the globe, such as Russian firm Apis Cor’s spartan concrete house, which the company says it built in 24 hours for $10,000; and Chinese firm Winsun’s five-story apartment block, produced with a behemoth waste-recycling printer.
One of the most intriguing projects is the YRYS Concept House being built by 18 partners, including French construction company Maisons France Confort and large-scale 3D printer company XtreeE. Using injection molding to press layers of rapidly setting concrete, XtreeE created a perforated wall and four structural columns supporting the upper floor’s rooms.
Jean-Daniel Kuhn, co-founder of XtreeE, points out that France’s architectural history is significantly defined by concrete: Le Corbusier’s preferred material béton brut, French for “raw concrete,” is the basis of Brutalist architecture. But one of XtreeE’s governing principles is to drastically reduce the consumption of concrete. “The world is built in concrete,” says Kuhn. “The production of cement, which is the key ingredient of concrete, generates eight percent of carbon emissions globally. Concrete is a fantastic material, but we want to see if we can use it in a better way: only where structurally necessary.”
Case 3: Artificial Coral Reefs
XtreeE is also producing what it calls “the world’s first 3D-printed concrete artificial reef.” Partnering with the marine engineering firm Seaboost, XtreeE designed and manufactured a porous concrete system to restore a lost ecological habitat at Calanques National Park in the Mediterranean Sea, off France’s southern coast.
Kuhn says the irregular tunneling shapes of the 3D-printed artificial reef have been modeled to encourage the return of species of fish, algae, mollusks, and coral populations that began to decline in the 1970s and 1980s due to wastewater emissions from the city of Marseille. The “reef” replicates the pockets and caves of the original limestone substrate, giving vulnerable species protection from predators.
Though Kuhn says 3D printing is still not cost efficient for many uses, he sees this changing as government policies—such as initiatives by the United Arab Emirates to 3D print 25 percent of all new buildings by 2030 and the UK’s National Strategy for Additive Manufacturing—begin to drive market shifts. “I think what is happening with 3D printing is similar to what happened with BIM,” Kuhn says. “The impact for material savings is so massive and governments are beginning to say, ‘this makes sense from an environmental standpoint.’”
Case 4: Pavilions and Bandshells
Through a process called cellular fabrication (C‐Fab), Tennessee-based Branch Technology can transform an architectural software model from virtually any platform—Autodesk AutoCAD, Revit, Maya—into a freeform lattice structure. These hollow structures are then printed by algorithmically controlled robots and act as a formwork to fill with traditional building materials. “It’s an analogy to how we are made on the cellular level,” says Branch Technology founder and CEO Platt Boyd. “The 3D-printed components act like the outer bounds of the cell. The strength is brought about with the filling material, the blood and water.”
In June 2018, the firm unveiled reportedly the largest 3D-printed structure in the world, a 42-foot diameter, 20-foot tall bandshell for OneC1TY in Nashville. The lightweight carbon-fiber structure, commissioned by Houston developer Cambridge and designed and built in partnership with CORE Studio’s Thornton Tomasetti, complies with Nashville’s building codes, which require it to withstand one inch of ice buildup, 10–12 inches of snow, and 90-mile-per-hour wind loads.
Though initial analysis suggested that the large spans would require steel substructures for support, subsequent studies showed that a curvilinear geometric design could eliminate the need for steel except at the foundation. This meant the project could remain within budget, at roughly half the cost of a similar steel structure.
“I am an architect, and often we’re constrained to make cookie-cutter boxes,” Boyd says. “Parametric architecture is doing really interesting things, but it’s been limited to renderings or ‘starchitects’ doing $800-to-$1,500-per-square-foot projects. I’m excited about the prospect of bringing these creative designs within normal construction budgets.”