The world’s largest concrete 3D printed pedestrian bridge has been completed in Shanghai, according to a team from Tsinghua University and the Shanghai Wisdom Bay Investment Management Company.
Measuring in at 26.3 metres long and 3.6 metres wide, the bridge’s structure was inspired by the ancient Anji Bridge in Zhaoxian, China.
It uses a single arch to bear the load, with the distance between the abutments being 14.4 metres, which was tested on a 1:4 scale physical model to perform structure failure testing.
The 3D printing concrete system that was used to create the bridge was developed by Professor Xu Weiguo’s team at Tsinghua University’s Zonia Land Joint Research Centre for Digital Architecture.
It uses technologies such as digital architectural design, printing path generation, operation control systems, printing tools, and has characteristics to allow for high printing efficiency, high molding precision and high constancy in prolonged work.
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There are three main parts to the system, the printing tool of the robot arm which avoids plugging during the extrusion process and collapse during the material’s layer stacking, a print path generation and operating system and a unique printing material formula.
Concrete components of the bridge were printed using two robotic arm 3D printing systems over 450 hours, costing around two thirds the price of a conventional bridge of a similar size due to the lack of templates and reinforcing bars.
The bridge itself is constructed of 44 hollow 3D printed concrete units, all made of composite materials comprised of polyethylene fibre concrete and other admixtures. A real time monitoring system has been installed into the bridge and includes a vibrating wire stress sensor and high-pressure strain monitoring system to collect real time force and deformation data.