Since 2004

The gridshells built by the Navier laboratory are made of a flat composite grid deformed elastically to obtain the shape desired. The design of the gridshell is based on many numerical simulations and on experience acquired during the fabrication of several full-scale prototypes.

Description of the research

The gridshells built by the Navier laboratory are made of a flat composite grid deformed elastically to obtain the shape desired. The design of the gridshell is based on many numerical simulations.

Design of a gridshell

At the beginning, a desired rounded shape is proposed by an architect. A first reflexion is necessary, to know if the shape proposed is suitable with the gridshell technology.  If it is, the design can start. The surface proposed by the architect is drawn in a modelling software. The surface is extended and two intersecting curves are drawn on the surface. The compass method can be performed to get a primary grid. The grid is then trimmed to get a geometrical primary gridshell. This process is explained in details in [Gridshells in composite materials : construction of a 300 m² forum for the Solidays’ festival in Paris – O. Baverel et al. (2013)].
The following step is the relaxation of the grid. An algorithm based on dynamic relaxation makes possible the investigation of the final natural shape of the gridshell. From a purely geometric grid obtained through compass method, the relaxation of the pre-stressed beams provides a grid which has a real mechanical meaning: the grid reaches its mechanical equilibrium. Once a satisfactory shape is obtained, the structure is numerically studied in response to the loads.

Construction of the prototype

The primary grid is assembled on the ground. The connections have a rotational degree of freedom in the plane of the grid so the quadrangles forming the grid can deform easily in the plane of the grid. Then, the erection of the grid is done, for example with the help of cranes. Each beam located on the edge of the grid is brought to its correspondent anchorage. The grid is then braced with a third layer of beams which confers its high stiffness.

People

Institutions

Laboratoire Navier,

Ecole Nationale des Ponts et Chaussées

  • All
  • Architectural Geometry
  • Gridshell
  • Active Bending
  • Composite Material

 Gridshells without kink angle between beams and cladding panels – X. Tellier et al. (2018)

Author

Xavier Tellier, Cyril Douthe, Olivier Baverel, Laurent Hauswirth

Abstract

In double-curvature gridshells covered with rigid flat panels, panels cannot lay flat on the top surface of beams. In many cases, costly elements need to be inserted in-between to insure a proper beam-panel connection. Precedent research on the geometric rationalization of gridshells has mostly focused on minimizing cladding panel curvature, simplifying node and beam fabrication, and allowing for repeatability of elements. The connection between beams and panels has received very little attention. This paper explores the possible gridshell geometries under the constraint of having a full planar contact between beams and cladding panels. A strategy that consists of folding panels is studied in details. It turns out that a rich variety of panel shapes and folding patterns is possible. Two generation methods for such shapes are proposed: a method for quad meshes of revolution covered with folded panels, and a method for folded hexagonal panels based on the projection algorithm developed by Bouaziz et al. The resulting structures are of particular interest for opaque doubly curved facades covered with metal sheets or other foldable material. The good contact between beams and panels also offers the possibility to use the panels as bracing elements. Hence the proposed method proves to be efficient for construction purposes, but also for mechanical behavior.

Status

Published

Journal

Proceedings of the IASS 2018

Links

> Full text

 Discrete CMC surfaces for doubly-curved building envelopes – X. Tellier et al. (2018)

Author

Xavier Tellier, Cyril Douthe, Olivier Baverel, Laurent Hauswirth

Abstract

Constant mean curvature surfaces (CMCs) have many interesting properties for use as a form for doubly curved structural envelopes. The discretization of these surfaces has been a focus of research amongst the discrete differential geometry community. Many of the proposed discretizations have remarkable properties for envelope rationalization purposes. However, little attention has been paid to generation methods intended for designers.
This paper proposes an extension to CMCs of the method developed by Bobenko, Hoffmann and Springborn (2006) to generate minimal S-isothermic nets. The method takes as input a CMC (smooth or finely triangulated), remeshes its Gauss map with quadrangular faces, and rebuilds a CMC mesh via a parallel transformation. The resulting mesh is S-CMC, a geometric structure discovered by Hoffmann (2010). This type of mesh have planar quads and offset properties, which are of particular interest in the fabrication of gridshells.

Status

Published

Journal

Advances in Architectural Geometry 2018

Links

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 Building elastic gridshells from patches – P. Marquis et al. (2017)

Authors

Marquis P., Cersosimo A., Douthe C.

Abstract

To be able to build elastic gridshells, it is necessary to define and build the flat grids that will be deformed into the final 3D shapes. For complex topologies, this flattening is not possible without separating the grid into independent sub-grids which will subsequently be assembled. The purpose of the proposed paper is therefore the investigation of such construction from patches. A systematic study of various strategies for patch cutting by grid offset is presented on a toroidal form. The different propositions are analyzed in terms of their influence on the final form, on the forces in the connectors, and on the equivalent flat area of the patches. A discussion on the way to deal with short beams generated by the method closes the study.

Date

September 2017

Conference

IASS 2017

Links

> permalien
>pdf

 The ephemeral cathedral of Créteil : a 350m2 lightweight gridshell structure made of 2 kilometers of GFRP tubes – L. du Peloux et al. (2015)

Authors

L. du Peloux, Frédéric Tayeb, Jean-François Caron, Olivier Baverel

Abstract

The Ephemeral Cathedral of Créteil (Paris, France) is a gridshell structure made of composite materials. Built in 2013, this religious edifice of 350m2 is a temporary church meant to gather the parishioners during the two-years renovation of their permanent cathedral. This large-scale prototype represents a first in the building industry, which still shows excessive apprehension for the use of non-traditional materials such as composites, especially when it comes to structural applications. Based on a previous successful experience the gridshell was prefabricated and erected by the parishioners themselves.

Date

May. 2015

Conference

CIGOS 2015 (Paris, France)

Links

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 Design and Realisation of Composite Gridshell Structures – F. Tayeb et al. (2015)

Authors

F. Tayeb, B. Lefevre, O. Baverel, J.-F. Caron, L. du Peloux

Abstract

This paper deals with the gridshells built by the Navier laboratory in the last ten years. The numerical conception is developed, from the draft made by architects up to the final structure. Several numerical tasks are performed to design a gridshell. The geometry of the gridshell is first considered. Then, an important iterative step mixing geometry and mechanical considerations is carried out. In particular, it is explained how the naturally straight beams are bent together during a very quick step leading to the final shape. Thanks to this active bending, double-curvature shapes are made and offer many interests like high stiffness for a light weight structure. Lastly, the geometry of the membrane is drawn based on the numerical final geometry of the gridshell. The improvements of gridshells, including safety considerations as well as practical considerations are also developed, through the four gridshells recently built. Finally the model is improved to take into account the torsion which can have an important effect, especially when the beams have a rectangular cross section.

Date

2015

Journal

Journal of the IASS

Links

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> bibtex

 Faith can also move composite gridshells – L. du Peloux et al. (2013)

Authors

L. du Peloux, F. Tayeb, O. Baverel, J-F. Caron

Abstract

This paper presents the overall design and construction process of a gridshell in composite materials at Créteil, in Paris suburb. This religious edifice of 350m² is a temporary cathedral meant to gather the parishioners during the two-years renovation of their permanent cathedral. It can accommodate up to 500 people and complies with all the required performances for such a building: structural stiffness, fire safety, waterproofness, lightning, thermal comfort, etc. This project arises thanks to a long-term collaboration between T/E/S/S and NAVIER and marks the accomplishment of a ten-years research project in the area.

Date

Sept. 2013

Conference

IASS 2013 (Wroclaw, Poland)

Links

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> bibtex

 Gridshells in composite materials : construction of a 300 m² forum for the Solidays’ festival in Paris – O. Baverel et al. (2013)

Authors

O. Baverel, J-F. Caron, F. Tayeb, L. du Peloux

Abstract

Composite materials are well known for their low density, high strength and high resistance against corrosion and fatigue; but so far only few constructions have been built with these materials. This article shows how com- posite materials might be an original and profitable solution for lightweight structures called gridshells. In this paper, the principal characteristics of gridshells are recalled first and a dem- onstration that glass fiber reinforced polymers are suitable for these structures is shown. Then the concept is applied to a functional structure built to house people in a festival. The form-finding of the structure, as well as the construction and some improvements are included.

 Gridshell in composite materials: towards wide span shelters – Douthe et al. (2007)

Authors

C. Douthe, O. Baverel, J.-F. Caron

Abstract

In 1975, the gridshell of Mannheim’s Bundesgartenschau revealed the extraordinary aesthetic potential of a new type of lightweight structures with very interesting mechanical properties; it however did not become widespread. This article shows how composite materials can be an original and profitable solution for such constructions. In the first section, the authors recall the principal characteristics of gridshells. They explain then why glass fibres reinforced polymers provide a very attractive solution for this kind of application. The second section is dedicated to the numerical modelling of the structure. The basic principles of the dynamic relaxation method are presented. The third and principal section shows the results of the measures taken on the prototype built at the Navier Institute and compares them with the results of the numerical simulations. Finally the authors conclude on the potential of such structures for larger span constructions.

Date

2007

Journal

 Journal of the I.A.S.S.

Links

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> pdf
> bibtex

 Formfinding of a grid shell in composite materials – C. Douthe et al. (2006)

Authors

C. Douthe, O. Baverel and J.-F. Caron

Abstract

The advantages of the use of glass fiber composites for grid shell are presented. The shape of grid shells results from a post-buckling state of tubes. To bypass the difficulty to predict the geometry of the final equilibrium state, the large rotations which occur during the erection process are modelled using the dynamic relaxation algorithm. This paper proposes an adaptation of this method for structures prestressed by bending through the development of a computer program. It includes the validation of this numerical tool through comparisons with a finite elements software. Then an application to the form-finding of a grid shell and the study of its stability under standard loading conditions will be presented. Finally the authors conclude on the technical and economic feasibility of this composite grid shell.

Date

2006

Journal

Journal of the IASS

Links

> permalien
>pdf

A collection of our built projects. Coming soon

A selection of pictures of elastic gridshells in composite materials. Coming soon

Coming soon