3D Printed Concrete Bridge

A 3D printed concrete bridge was built for the “Time Space Existence” exhibition during the 2021 Venice Architecture Biennale.  The exhibition was hosted by the European Cultural Center.  It displayed structural elegance of a concrete bridge constructed using robotics, 3D printing and sophisticated geometry.  

Striatus

The project is known as Striatus, which literally means “a small striped semiterrestrial eastern American squirrel with cheek pouches”.  In this case, the stripes refer to the 3D printing process which fabricated the structure in layers or stripes.  The design team consisted of Block Research Group (BRG) at ETH Zurich and Zaha Hadid Architects Computation and Design Group (ZHACODE), in collaboration with incremental3D and Holcim. 

Structural elegance through study of natural systems

Many architects and engineers have passionately worked on finding ways to create structural elegance by incorporating natural systems in their designs.   Pier Luigi Nervi’s Palazzetto dello sport for the 1960 Olympics in Rome utilized the idea of people lifting a dome as an inspiration to conceive structural supports for the dome.  Felix Candela experimented with reinforced concrete structures distinguished by thin curved shells to create elegant structures such as the Palacio de los Deportes de la Ciudad de México for the 1968 Olympics.  Santiago Calatrava has become a household name because of his ingenious use of natural forms to create structures that exhibit elegance and movement.  His poetic projects such as the Pont de Montolivet unite structural efficiency with movement.  They also fit neatly into their urban context. 

Pont de Montolivet by Santiago Calatrava ¹

Pier Luigi Nervi’s Palazzetto dello sport for the 1960 Olympics in Rome ²

Structural elegance through geometry – Formation/Deformation

What is the most efficient structural form for an arch?  This question has puzzled many thinkers and engineers.  In 1675, Robert Hooke wrote a series of anagrams in his book on heliscopes.  One of them was deciphered by Richard Waller in 1701 to mean, “As hangs the flexible line, so but inverted will stand the rigid arch”.  An inverted catenary is then the theoretically correct line for an arch.  That was a profound observation, which arose from an intuitive understanding of forces acting on a catenary cable.  I had an opportunity to teach a class on structures to architecture students that focused on the formative stage of design process.  It is during the formative stage when major characteristics of a structure are defined.  In a 1991 presentation at Harvard University, I elaborated on the interrelationships between loads, geometry, and the behavior of structures. ³

Structural elegance through geometry – Formation/Deformation ³

Advanced computation, robotics and 3D printed concrete bridge

The Striatus bridge achieved strength through geometry and relied on compression only without the use of reinforcement.  By using advanced technologies, from computational design and engineering to robotic manufacturing and 3D printing, Striatus was able to revive traditional master builders’ techniques.  The bridge was designed to make efficient use of materials, significantly reducing the environmental footprint.  The dry joints of 3D printed concrete bridge were designed to make recycling and reuse of building components possible after the dismantling of structure.    

Significance of this exhibit

The idea of using geometry to derive an efficient structural form is not new.  The idea of 3D printing large structures is also not new. The real significance of this exhibit is the demonstration of computation, robotics, and 3D printing to build a concrete structure at a major public venue.  It would be interesting to see how this structure would function in an actual urban context. 

• References
• Title Image:  Resource on. (n.d.). Egnyte. Retrieved September 16, 2022, from https://zahahadid.egnyte.com/fl/yaFVC39Zrm#folder-link/
• 1          Lauren Manning from New York, USA, CC BY 2.0, via Wikimedia Commons.  File:Calatrava bridge.Jpg. (n.d.). Wikimedia.org. Retrieved September 16, 2022, from https://commons.wikimedia.org/wiki/File:Calatrava_Bridge.jpg
• 2          MaT12Vi, CC BY-SA 4.0, via Wikimedia Commons.  File:Palazzetto Nervi.Tif. (n.d.). Wikimedia.org. Retrieved September 16, 2022, from https://commons.wikimedia.org/w/index.php?curid=93888606
• 3          Architecture: Design Implementation : Selected Papers from the 9th Annual ACSA Technology Conference. (1991). United States: Association of Collegiate Schools of Architecture Press. Formation/Deformation: Deriving Structural Forms Through a Study of Cable Deformations, ACSA Technology Conference, Conference Proceedings, pp 104-107