A pioneering Dutch project shows how 3D printing could reshape construction with lighter structures, lower emissions, and faster builds.
The 26-foot-long Gemert bridge across the Peelse Loop Canal, the world's first 3D-printed concrete bridge, was inaugurated in 2017. A pedestrian bridge composed of 3D-printed concrete components has been installed in Gemert, the Netherlands.
This is the very first bridge of its kind ever to be constructed anywhere in the world. It was designed in such a way that it would be comprised of six lattice-like beams, which were prestressed end-to-end. In doing so, the researchers were able to cut down on their consumption of materials by nearly 40 percent, without compromising any of their design objectives. TU/e professor Theo Salet.
Its 800 printed layers of reinforced, pre-stressed concrete now carry hundreds of cyclists a day. The bridge demonstrates a new, lighter approach to low-carbon infrastructure, cutting waste and CO₂ by depositing concrete only where needed. The 26-foot-long Gemert bridge across the Peelse Loop Canal, the world’s first 3D-printed concrete bridge, was inaugurated in 2017 when local authorities and engineers crossed it for the first time.
The bridge was printed in segments and assembled using standard abutments and tensioning cables with a design life comparable to traditional bridges. Although the bridge is engineered to conform to Dutch building standards, there was a significant reduction in the quantity of cement used: 3D printing “uses far less concrete, which saves resources,” as observers have noted. This reduction in the use of cement is very important since cement manufacturing accounts for about 8 percent of all CO₂ emissions worldwide.
The traditional bridge construction process requires the use of concrete beams cast using molds. The manufacturing process requires large amounts of cement production, which releases up to 1.6 billion tonnes of carbon dioxide annually . Engineers have thus started looking for more environmentally friendly methods of building even small-span bridges.
This was precisely the challenge that the Gemert bridge faced: to construct a light and environmentally friendly bicycle/pedestrian bridge that would last for at least 50 years without compromising safety. As the project’s backers explain, the printer “deposits the concrete only where it is needed,” in contrast to filling an entire mold. That means less cement per meter—on this bridge roughly 40% less concrete—while still reaching normal strength. According to, this “uses far less concrete, which saves resources”.
In fact, TU/e’s researchers estimate the printing process is “roughly three times faster than conventional concrete techniques”, since no formwork must be built or removed and reinforcement is placed on the fly. The Gemert bridge proposal was based on six similar hollow beams that were around one meter long, for a total of six meters in span. Witteveen+Bos was responsible for structural design and created a predesigned geometry of lattice beams in 3D software modeling.
As one engineer put it, the use of “pre-tensioned printed elements was a unique development in the 3D concrete printing world”. Each beam in the shop was printed in 133 layers . In the process of printing, a steel cable with a diameter of 2 mm was inserted into each new layer. As TU/e reports, this embedded cable “effectively handles the tensile stress” the concrete would see in service.
In other words, the result of the process was an aggregated band, a quick-setting and thixotropic concrete over steel wire. A special type of mortar was employed in the process, known as Weber Beamix 3D-mortar, which is a pumpable and quick-setting concrete formulated specifically for robotically-printed concrete structures. This is not the same as regular ready-mix concrete, which needs to be shaped on-site. Bridge components were printed using the TU Eindhoven gantry robot printer.
The giant 3D printer has two pumps and a 4-axis gantry robot that spans 9×4.5×3 meters. It prints layers of concrete, which are about 1 cm high , according to a pre-programmed path. A wire feeder machine puts a steel cable in the middle of each layer. Since the beams were printed horizontally, the completed blocks had to be turned 90 degrees before construction.
No formwork or scaffolding was required; rather, the concrete was continuously poured until it reached the desired shape. In other words, there is no wastage of materials since the printing process deposits only in the required areas. ). As a TU/e researcher explained, this method meansof pouring into a full mold.
Water, sand, cement and admixtures were precisely mixed on demand. The quick set-time kept the print moving and prevented sagging. The quality control process was embedded into the design and construction processes.
Each layer bonding process and printing offset were controlled for up to ±2 mm. Testing samples of printed concrete were used to ensure the expected strength . Wires guaranteed that after curing, each block would act like a prestressed beam. Engineers conducted in-laboratory loading experiments on each completed segment; specifically, a 1-m segment was put under compressive loading and bending/tensile loading.
Despite having a hollow body structure, the printed segment only started showing cracks at approximately 80% of its predicted strength limit. At the site, the six printed segments were positioned onto standard concrete abutments. With laser guidance, contractors applied epoxy to joint the blocks end-on. After which, steel tendons from Dywidag were passed into the ducts of the blocks, with anchorage provided at both ends.
The resulting longitudinal pre-tensioning of the whole structure compressed the joints. Since everything was prefabricated, erection was fast; in fact, erection was completed within several hours to join all the 6 m span sections together. Subsequently, testing was done on-site. During testing, an official test load of up to 2 tons was put on the bridge .
According to the engineers involved, the design would safely support loads equating to approximately 40 trucks. Bicycling over the bridge by local authorities affirmed the structural integrity of the design. Critically, the bridge meets all Dutch highway standards and has the required 50-year service life. The digital workflow – from CAD to print file to physical beam – ensured that the as-built geometry exactly matched the design model.
This “top-down” approach means any site change would require a new digital model and reprint of parts. Indeed, one lesson noted by the team was the need for careful coordination: “all information gathered in the design process can now also be passed directly to the implementation,”The project also reinforced the value of interdisciplinary collaboration: architects, structural engineers, materials scientists and concrete technologists all had to work in concert.
In particular, customizing the Weber Beamix print mortar was essential. The mix was “thixotropic” so it could flow through hoses and extruders yet quickly regain stiffness. Admixtures and viscosity agents were tuned so that successive layers could bear weight immediately. Saint-Gobain reports their 3D printing mixes now achieve more than 49% lower CO₂ than regular mortar, and the Gemert bridge helped prove out these formulations.
The Gemert bike bridge vividly illustrates how digital fabrication can cut waste. By eliminating formwork and only building the needed geometry, the team saved roughly 40% of the concrete. That translates to a similar drop in cement use and embodied carbon. As BAM Infra’s director Marinus Schimmel explained, 3D printing “does not require any auxiliary materials, such as formwork.
This produces significantly less waste and we need less scarce raw materials… a positive effect on the amount of CO₂ emissions during the bridge production”. The faster schedule also reduces equipment hours. In practice the printer ran for about 3 months , whereas a traditional cast bridge might have taken 3–4 times longer.
The site assembly took only a single day – all six segments were lifted and fit in place in under six hours – saving roughly 50–70% of the onsite labor typically needed for formwork, waiting, and striking. This case study makes clear that the main cost of change is up-front design and material R&D, not the printing itself. Once the digital model was finalized, the printer simply “rolled out” the structure.
In practical terms, each new bridge design can be realized with identical effort once the robot and mix are ready. Salet notes, “Thanks to the use of robots, each design can be realized in a unique way with the same effort,” reinforcing that different geometries no longer cost extra in labor. In short, the Gemert span shows how 3D concrete printing can reshape infrastructure to be lighter, faster, and greener.
Srishti started out as an editor for academic journal articles before switching to reportage. With a keen interest in all things science, Srishti is particularly drawn to beats covering medicine, sustainable architecture, gene studies, and bioengineering. When she isn't elbows-deep in research for her next feature, Srishti enjoys reading contemporary fiction and chasing after her cats. InterviewsInterviews
Additive Manufacturing Bridge Design Civil Engineering Concrete Construction Technology Structural Engineering Sustainable Infrastructure TU Eindhoven
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