Striatus - 3D concrete printed masonry bridge, Venice, Italy, 2021

Project by the Block Research Group (BRG) at ETH Zurich and Zaha Hadid Architects Computation and Design Group (ZHACODE), in collaboration with incremental3D (in3D), made possible by Holcim.


Striatus is an arched, unreinforced masonry footbridge composed of 3D-printed concrete blocks assembled without mortar. Exhibited at the Giardini della Marinaressa during the Venice Architecture Biennale until November 2021, the 16x12-metre footbridge is the first of its kind, combining traditional techniques of master builders with advanced computational design, engineering and robotic manufacturing technologies.

The name “Striatus” reflects its structural logic and fabrication process. Concrete is printed in layers orthogonal to the main structural forces to create a “striated” compression-only funicular structure that requires no reinforcement.

A new language for concrete

Proposing a new language for concrete that is structurally informed, fabrication aware, ecologically responsible and precisely placed to build more with less, Striatus optimises the interrelated properties of masonry structures, 3D concrete printing (3DCP) and contemporary design; presenting an alternative to traditional concrete construction.

Strength through geometry

Striatus is an unreinforced concrete structure that achieves strength through geometry. Concrete can be considered an artificial stone that performs best in compression. In arched and vaulted structures, material can be placed precisely so that forces can travel to the supports in pure compression. Strength is created through geometry, rather than an inefficient accumulation of materials as in conventional concrete beams and flat floor slabs. This presents opportunities to significantly reduce the amount of material needed to span space as well as the possibility to build with lower-strength, less-polluting alternatives.

Sustainable digital concrete

Circular by design, Striatus places material only where needed, significantly reducing its environmental footprint. Built without reinforcement and using dry assembly without binders, Striatus can be installed, dismantled, reassembled and repurposed repeatedly; demonstrating how the three R’s of sustainability (Reduce, Reuse, Recycle) can be applied to concrete structures.

  • Reduce: Lowering embodied emissions through structural geometry and additive manufacturing that minimises the consumption of resources and eliminates construction waste. 
  • Reuse: Improving circularity and longevity. Unlike conventional reinforced concrete structures, Striatus is designed to be dry assembled without any binder or glue, enabling the bridge to be dismantled and reused in other locations. 
  • Recycle: By ensuring different materials are separated and separable, each component of Striatus can easily be recycled with minimal energy and cost. 

Robotic 3D concrete printing

Unlike typical extrusion 3D printing in simple horizontal layers, Striatus uses a two-component (2K) concrete ink with corresponding printing head and pumping arrangement to precisely print non-uniform and non-parallel layers via a 6-axis, multi-DOF robotic arm. This new generation of 3D concrete printing in combination with the arched masonry design allows the resulting components to be used structurally without any reinforcement or post-tensioning.

Computational design-to-construction integration

Integrating design, engineering, fabrication and construction, Striatus redefines conventional interdisciplinary relations. The precise manufacturing of the blocks was enabled by well-defined data exchange between the various domain-specific software toolchains involved in the process. This co-development approach was facilitated through the use of COMPAS, an open-source computational framework for collaboration and research in the AEC industry.

Disruptive outlook

Striatus offers a blueprint for building more with less. Created with the same structural principles and a similar fully-integrated computational design-to-fabrication approach that form the basis of the vaulted, rib-stiffened, unreinforced concrete floors being developed by the Block Research Group in partnership with Holcim, Striatus proposes an alternative to the standard inefficient floor slabs within any building.

Compared to typical reinforced concrete flat floor slabs, this new floor system uses only 30% of the volume of concrete and just 10% of the amount of steel. The very low stresses within the funicular structure also enable the use of low-embodied-carbon concrete that incorporates high percentages of recycled construction waste. Prefabricated and dry-assembled, and therefore fully demountable and reusable, this floor system is easily and cleanly recyclable at end-of-life.

With an estimated 300 billion square metres of floor area to be constructed worldwide over the next 30 years, and floors comprising more than 40% of the weight of most high-rise buildings (10+ storeys), introducing the principles demonstrated by Striatus would truly disrupt the construction industry — transforming how we design and construct our built environment to address the defining challenges of our era.

More info

Built at the Giardino della Marinaressa in Venice, Italy for the 2021 biennial architecture exhibition “Time Space Existence”, hosted by the European Cultural Centre (ECC).

Discover more here:

Short credits

  • ETH Zurich - Block Research Group, ETH Zurich (BRG)
  • Zaha Hadid Architects - Computation and Design Group (ZHACODE)
  • in collaboration with incremental3D
  • made possible by Holcim.

Full credits


  • ZHACODE: Jianfei Chu, Vishu Bhooshan, Henry David Louth, Shajay Bhooshan, Patrik Schumacher
  • ETH BRG: Tom Van Mele, Alessandro Dell’Endice, Philippe Block

Structural engineering

  • ETH BRG: Tom Van Mele, Alessandro Dell’Endice, Sam Bouten, Philippe Block

Fabrication design

  • ETH BRG: Shajay Bhooshan, Alessandro Dell’Endice, Sam Bouten, Chaoyu Du, Tom Van Mele
  • ZHACODE: Vishu Bhooshan, Philip Singer, Tommaso Casucci

3D concrete printing

  • incremental3D: Johannes Megens, Georg Gasser, Sandro Sanin, Nikolas Janitsch, Janos Mohacsi

Concrete material development

  • Holcim: Christian Blachier, Marjorie Chantin-Coquard, Hélène Lombois-Burger, Francis Steiner
  • LafargeHolcim Spain: Benito Carrión, José Manuel Arnau

Assembly & Construction

  • Bürgin Creations: Theo Bürgin, Semir Mächler, Calvin Graf
  • ETH BRG: Alessandro Dell’Endice, Tom Van Mele


  • ETH BRG: Alessandro Dell’Endice, Tom Van Mele
  • Holcim Switzerland & Italy: Michele Alverdi
  • LafargeHolcim Spain: Ricardo de Pablos, José Luis Romero

Additional partners

  • Ackermann GmbH [CNC timber formwork]
  • L2F Architettura [site measurements]
  • Pletscher [steel supports]
  • ZB Laser [lasercutting neoprene]


  • ZHACODE: Jianfei Chu, Cesar Fragachan, Vishu Bhooshan, Philip Singer, Edward Meyers, Shajay Bhooshan
  • ETH BRG: Tom Van Mele, Alessandro Dell’Endice, Philippe Block
  • incremental3D: Alexander Gugitscher, Sandro Sanin, Nikolas Janitsc
  • LBS Fotografia
  • naaro

Fact sheet


  • Maximum height = 3.5 m
  • Minimum head height = 2.2 m
  • Total surface area = 216 m2
  • Total covered area = 50 m2
  • Longest span = 15.10 m
  • Shortest span = 4.95 m
  • Material density of 3D-printed concrete = ~2350 kg/m³
  • Mass 3DCP blocks = 24.5 ton
  • Mass footings and tension ties = 5.2 ton

Voussoirs / Blocks

  • Number of voussoirs = 53
  • Thicknesses of voussoirs = 0.05m - 0.35 m
  • Mass of blocks = 217 kg - 783 kg
  • Volume (solid) of voussoirs = 19.18 m³

3D-printed concrete

  • Path lengths (per block) = 602 m - 1754 m
  • Total path length (all blocks) = 58 km
  • Total print time (all blocks) = 84 hours
  • Print layer heights = 4.46 mm - 11.98 mm
  • Print widths deck blocks = 25 mm - 50 mm
  • Print width balustrade blocks = 40 mm


Giardino della Marinaressa, Venice, Italy - 45°25'53.6"N 12°21'09.8"E


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