The Venice Bridge is built with old masonry and 3D printing

A small seaside park in Venice, Italy was recently modernized to include an innovative new concrete pedestrian bridge from the research arm of global contemporary design firm Zaha Hadid Architects. Like many of the company’s iconic projects, it features plunging lines, smooth curves, and the vaguely futuristic shape of something that appears to be built by or for space robots.

What’s important with the concrete bridge is what it doesn’t have. Using a construction technique inspired by ancient masonry, the bridge does not require steel reinforcement, bonding mortar, or the large amount of carbon-intensive concrete that a conventional construction structure would require.

The bridge is able to withstand, and even withstand the weight and forces of regular use, thanks to a highly detailed, computerized design that used 3D printing to accurately generate 53 hollow concrete pieces that stack up in a structure as solid as stone.

The bridge was designed by Shajay Bhooshan, co-founder of Zaha Hadid Architects Computation and Design Group ZHACODE and Philippe Block, professor at the Institute of Technology in Architecture at ETH Zurich, in collaboration with the 3D printing company incremental3D and the global building materials company. Holcim. Like the ancient stone bridges and cathedrals, the structure was designed in an old style but with new material precision. Installed as part of the current Venice Architecture Biennale, the bridge is an attempt to prove that ancient and modern techniques can be combined to create better structures.

“Many masonry structures are standing after centuries because of their ability to move and settle. They’re still there, they’re very sturdy but not in a way that modern engineering allows, ”says Block. Arched stone bridges from Roman times, for example, have remained intact for centuries due to their simple compression and weight. “It’s a beautiful thing that we want to reintroduce into modern architecture and the practice of engineering. “

The parts of the bridge have been 3D printed to be inconspicuous pieces that are mostly hollow, with only small concrete struts inside. Computer design was used to determine how each part could support its weight and how the 53 parts of the bridge could interlock and provide structural strength entirely through compression. This approach reduces the amount of concrete and eliminates the need for steel rebar that concrete structures require. Fewer materials reduce the overall cost of construction, and the relative ubiquity of concrete means that this type of construction could potentially happen anywhere.

“You place the material exactly where it’s needed,” says Bhooshan, who developed the design as part of his doctoral research at ETH Zurich.

Rather than the typical 3D printing approach that poses a uniform blend line over and over again to build simple walls, Bhooshan and Block worked with Holcim to develop a special 3D printing approach that can pose varying width. of material, allowing a more complex structure shape while using less steel and concrete. Non-parallel shapes open up new aesthetic opportunities for 3D concrete printing. “It’s really about starting with the design and thinking about how best to use the materials,” says Francis Steiner, head of digital design and manufacturing at Holcim. “This is where we see the future of 3D concrete printing.”

Built earlier this summer on a simple wooden bracing structure, the bridge also features small concrete slabs and steel tension ties at the five points of contact with the ground, as well as steel steps. Because the bridge does not require mortar or glue to hold it together, it can be dismantled and rebuilt elsewhere as needed (there may come a time when buildings and infrastructure need to be moved quickly for cities to adapt to climate change. ). Block says the team is currently in the process of finding a second home for the bridge.

Despite its location in the lagoon city of Venice, the bridge is located in the middle of a park and does not actually cross the water. But that didn’t stop it from being used, according to Bhooshan. Since opening, it’s been popular with kids, dog walkers, and park visitors who move just to roost and gaze at the ocean. “It turned out to be a very social space,” he says. “It was quite a surprising and pleasant and happy coincidence to discover.”