The School of Architecture at Tsinghua University (Beijing, China), in association with the Shanghai Wisdom Bay Investment Management Company, recently completed a project to design and develop a concrete 3D-printed pedestrian bridge for Shanghai’s Wisdom Bay Industrial Park. At 26.3 m long and 3.6 m wide, the bridge is the largest of its type in the world.
The 3D-printed concrete bridge project was led by Xu Weiguo, a professor and chair of Tsinghua University’s School of Architecture. Inspired by China’s Anji Bridge, the world’s oldest open-spandrel segmental arch bridge, Xu’s bridge is designed so that a single arch bears the load while supported by abutments spaced 14.4 m apart. The bridge’s aesthetic appeal is heightened by handrails shaped like flowing ribbons and pavements that take the form of brain corals.
Using their previously developed 3D printing concrete system, Xu’s team integrated a variety of innovative digital design and printing path technologies into that system. The 3D-printed concrete is made from composite materials that contain polyethylene fiber concrete with various admixtures. The bridge itself is composed of 44 hollowed-out 3D-printed concrete units, while the handrails and pavements are divided into 68 and 64 units, respectively.
Prior to printing the bridge materials, Xu and his team built a 1:4 scale physical model of the bridge in order to assess its bridge’s ability to meet the load requirements of pedestrian traffic. From there, two robot arms printed the bridge’s concrete components over a 450-hour period, a process which resulted in 33% savings in material costs.
The Tsinghua University team installed a monitoring system into the bridge to provide them with real-time force and deformation data. Along with the vibrating wire stress sensors and high-precision strain monitoring system, the researchers will be able to determine how their 3D-printed concrete materials perform under real-world conditions. Over the long term, they hope that the successful completion of the Wisdom Bay Industrial Park pedestrian bridge will encourage Chinese construction companies and research institutions to employ concrete 3D printing designs in their projects.