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Arroyo Bridge

August 31, 2021

In Los Angeles, Students Complete a Complex Pedestrian Bridge with Robotic Assistance

A collaboration between MADWORKSHOP and students at the University of Southern California’s School of Architecture, the intricate steel bridge was digitally modeled and robotically assembled.

By: Jessica Ritz

Completed in May 2020, Los Angeles’s 80-foot-long tubular steel Arroyo Bridge is the finished product of a collaboration that goes back to 2013. That’s when Mary and David Martin’s MADWORKSHOP, a nonprofit educational foundation, offered funding to an undergraduate class at the University of Southern California’s School of Architecture to design a pedestrian bridge that would connect an enchanting yet challenging privately owned site on the city’s west side.

It’s like this
ethereal thing.

R. Scott Mitchell, associate professor of architectural practice at the University of Southern California and founder of the firm Gigante AG

The course was taught by R. Scott Mitchell, associate professor of architectural practice at USC and founder of the firm Gigante AG. “[Mitchell] and I have been on the same wavelength for years,” says David Martin, cofounder of the foundation, and a third-generation architect whose family legacy is inextricably tied to L.A.’s evolution.

Arroyo Bridge
Beneath the span of L.A.’s Arroyo Bridge, a fern garden leads into a flourishing landscape that includes Matilija poppies, buckwheat, and fruiting olive trees. The walkway’s dense tropical hardwood decking helps connect the innovative structure with the sensitively transformed natural environment. Courtesy © Iwan Baan

Once Mitchell’s students settled on a design that contains about 210 unique steel struts, Martin recalls that they faced “the problem of how we’re really going to build it.” The research arm of software company Autodesk in Boston became a key collaborator. The bridge’s steel components, digitally modeled using Autodesk software, were fabricated in Massachusetts, shipped to L.A., and test-assembled in master welder Juan Ramos’s studio before the final installation over the expanse.

Robots helped align the tubular elements—no two of which are alike— matching the precise geometries that the engineering dictated. Craftspeople then completed the on-site welding of the russet-hued steel structure. The Arroyo Bridge was an ideal vehicle to test collaborative robotics, especially since this fabrication method can scale to larger projects by playing to the strengths of precision robotics while allowing skilled workers to focus on tasks like welding complex curves.

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The result still leaves its designers awestruck. “It’s like this ethereal thing,” Mitchell says.

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