Full-scale construction prototype of the NEST HiLo shell roof

This full-scale experiment investigates the feasibility of spraying a textile reinforced thin concrete shell using a lightweight flexible formwork composed of a tensioned cable net as falsework and tailored fabric as shuttering. This one-to-one (with a bounding box of 20m x 10m x 5m) prototype can be seen as the dress rehearsal for the construction of the roof of the NEST HiLo project.

More info

The development and realisation of this full-scale, one-to-one prototype of the first layer of NEST HiLo's thin concrete shell represent a key milestone for the project, demonstrating the viability of the proposed lightweight, flexible formwork to form a complex concrete surface structure.

The purpose of this experiment is to investigate

  • the engineered material system, bespoke sprayed concrete and tailored carbon-fibre reinforcement mats, to achieve the extreme geometry of the shell;
  • the logistics, including sequencing of construction, involved in scaling up the concept of a tensioned flexible formwork;
  • the effectiveness of the control algorithms, supported by point-cloud scanning, developed to map the flexible formwork to the designed target geometry; 
  • the quality of the resulting architectural concrete on the thin and large surface structure.

Professional partners have been brought together to mimic real-life conditions so that the feasibility of this extreme construction innovation can be assessed.

Making-of movie

Check out how the unique concrete shell was designed, fabricated and constructed! Coming soon...

Virtual tours

Check out the amazing documentation by Zitronenwolf of different stages of the construction prototype:



ETH Block Research Group [BRG]
ETH Chair of Mathematical and Physical Geodesy
ETH Automatic Control Laboratory


Marti [general contractor]
Bürgin Creations [concrete works]
Doka [scaffolding]


Jakob [cables]
Bruno Lehmann [rods + cable net components]
Blumer Lehmann [timber]
Dafotech [steel supports + plates]
Bieri [fabric cutting + sewing]


ETH Zurich
NCCR Digital Fabrication
Holcim Schweiz




Cristián Calvo
Alessandro Dell'Endice
Philippe Fleischmann
Ursula Frik
Naida Iljazovic
Alexander Kobald
Juney Lee
Michael Lyrenmann
Ammar Mirjan
Mariana Popescu
Andreas Reusser
Matthias Rippmann
Alexander Nikolas Walzer
Hongyang Wang



Cable-net and fabric formworks for concrete shells

Cable-net and fabric formworks for concrete shells

This project investigates the feasibility of using both large cable nets with a secondary system of fabric shuttering as well as fabric directly as a formwork for concrete shells. These lightweight formwork systems reduce the need for seperate foundations of the formwork and allow unobstructed space underneath the shell during construction.

Active control of a cable-net formwork

Active control of a cable-net formwork

The use of tensioned formworks in concrete shell construction can reduce the demand on foundations, promote usable and unobstructed internal space during construction, encourage formwork re-use for repeated application, and greatly eliminate the material waste often experienced with traditional timber formwork and falsework. To understand the behaviour of such a net system prior to the pouring of the wet concrete, this research project investigates the fabrication, control and measurement systems needed to define a geometrically accurate net prior to concrete pouring, such that it will displace under the wet concrete self-weight to the correct final shape. The internal pre-stress forces as well as the forces and deflections at the boundary points also need careful consideration.


There are no linked publications.



ETH Zurich
Institute of Technology in Architecture
Block Research Group
Stefano-Franscini-Platz 1, HIB E 45
8093 Zurich, Switzerland

+41 44 633 38 35  phone
+41 44 633 10 53  fax

Copyright © 2009-2017 Block Research Group, ETH Zurich, Switzerland.