Diamanti: 3D-Printed, Post-Tensioned Concrete Canopy
Authors
Structural and Computational Design: Masoud Akbarzadeh, Hua Chai, Yefan Zhi, Maximilian E. Ororbia, Teng Teng, Pouria Vakhshouri, Mathias Bernhard (Polyhedral Structural Laboratory, University of Pennsylvania)
Structural Analysis and Material Calibration: Damon (Mohammad) Bolhassani, Fahimeh Yavartanoo, Javier Tapia (Advanced Building Construction Lab, City College Of New York)
Industry Partner: Karolina Pajak, Mylene Bernard, Leon Trousset (Sika Group Switzerland)
Structural Engineering Consultant: Paul Kassabian, Blaise Waligun (Simpson Gumpertz & Heger Group Boston)
Structural Test (Full-Scale): Cerib France, Eiffage
Structural Test (Half-Scale): Joseph Yost, Jorge Huisa Chacon (Department of Civil and Environmental Engineering, Villanova University)
3D-Printing Materials and Services (Full-Scale): Sika Group Switzerland, Carsey 3D
3D-Printing Materials and Services (Half-Scale): Eduard Artner, Martin Gutmann, Christoph Wallner, Oliver Balog (Baumit)
Project Date
2022-
Acknowledgements
This research is funded by the Advanced Research Projects Agency – Energy (ARPA-E) of U.S. Department of Energy (DE-FOA-0002625 2625-1538).
Description
This academia–industry collaborative project, Diamanti canopy, demonstrates the design and fabrication of a combined compression and tension funicular canopy with periodic anticlastic, diamond surfaces. The canopy is a part of the European Cultural Centre’s 2024 biennial exhibition, ‘Personal Structures’, in Venice, Italy, at the Giardini della Marinaressa. Utilizing both 3D concrete printing (3DCP) and post-tensioning technologies, the canopy spans 10m and is supported by a cross-laminated timber (CLT) platform. The structural form of this composite canopy directly considers both compressive and tensile forces, inherently developed in concrete structural systems, by distributing loads through its unique, minimal-mass geometry. The CLT platform suggests how the combination of a carbon-negative material and concrete can be used in contrast to common construction methods where concrete is typically used as the load-bearing support and wood as the spanning element. Hence, the lightweight design of the Diamanti canopy, spanning over and supported by the CLT platform, showcases the innovative use of these materials, while also satisfying the Venice Port Authority’s installation requirements.
The exhibited canopy goes beyond compression only by embracing tension as an unavoidable force in systems resilient to different loading scenarios. Hence, a combined form-finding and fabrication approach was developed to achieve the innovative structure with the intention of also minimizing carbon through reduced materials and recyclability. Through the design freedom enabled by the design approach, 3DCP, and the use of post-tensioning, the final design favorably has minimal reinforcement while achieving the desired structural performance. Overall, the Diamanti canopy demonstrates how, through the combination of modern technologies and the development of a non-restrictive, comprehensive design approach, new structural forms can be achieved that lead to enhanced sustainable practices.
The geometry-based structural design method of polyhedral graphic statics (PGS) provided the design freedom to achieve a structure that is capable of dealing with developed compression and tension forces. Polyhedral cells, defined from the resulting structural form, were used to contort periodic anticlastic surfaces, specifically the diamond triply periodic minimal surface (TPMS) geometry to align with the principal stress directions. The diamond TPMS unit’s geometry enhances the structural form’s geometric stiffness and inherently provides the internal conduits for the posttensioned cables, resulting in a fully integrated material structural system.
The overall design and fabrication approach in this work includes multiple intertwined innovative strategies that result in an extremely efficient structural system utilizing 3D concrete printing and post-tensioning that reduces the construction materials needed compared with conventional structural systems. The prefabrication strategy yields faster erection times, reduces soft construction costs, eliminates the need for formwork, allows for recyclability, and minimizes the overall carbon emissions of concrete construction.
