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.

Photo of a hydraulic press

Stress testing the scale model version of the bridge (Courtesy JCDA)

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.

Photo of a robot arm pouring patterned concrete

The bridge’s components were printed with hollow voids, necessitating 33 percent less material than a traditionally-manufactured structure. (Courtesy JCDA)

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.

Diagrams of a bridge

Bridge elevation (Courtesy JCDA)

Diagrams of a bridge

Bridge plan (Courtesy JCDA)

Diagrams of a bridge

Bridge sections (Courtesy JCDA)

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