Nabucco, Lausanne cathedral

Benches and bleachers

2018 Nabucco – benches & bleachers, Lausanne (CH)

In 2014, IBOIS laboratory presented at the Acadia 2014 Design Agency conference in Los Angeles a model of clipped wooden joint. By exploring the elastic properties of wood, the laboratory has developed a new male and female plug system, which once nested (or “clipped”) are able to hold two pieces of wood together without adding glue or metal. There is many opportunities and advantages for this system to be used in construction fields. If this principle started to be used, it could simplify the implementation, shorten the assembly time and reduce its cost.

In Novembre 2018, the Lausanne Cathedral has hosted 6 (4 + 2 additionnals) representations of Nabucco’s opéra. For that specific event, we developped a new wooden scenography, showing a technology transfert of the snap-fit joints developped by IBOIS laboratory. The scenography include benches and bleachers for spectators. Those benches are all in wood panels, assembled together thanks to a combination of snap-fit joints and mortise and tenon joints, for about 740 spectactors at each representation.

While Snap-fit joints can resist a certain retention force, they do not provide any shear resistance. In order to use this joint as a load-bearing connection for building components, snap-fit joints are combined with prismatic tab-and-slot joints, which receive the majority of the forces.

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Location Lausanne, Switzerland
Client Amabilis, Lausanne
Architect Yves Weinand Architectes sàrl, Lausanne
Timber Engineering Bureau d’Etudes Weinand, Liège
Technological Transfer

Laboratory for Timber Constructions
IBOIS EPFL
Prof. Dr Yves Weinand, Petras Vestartas, Loïc Pelletier, Martin Nakad

Completed Novembre 2018

The assemblage of the bench panels does not require specific tools nor any additional material such as glue or metal assemblie. This combination of integrated joints achieve a mechanical behavior equivalent to a screwed joint. Also the elements (pre-fabricated wood panels) can be transported to the construction site flat-packed and put together on site. This reduces the necessary transportation volume. Moreover, they can be quickly put together or disassembled if needed. Finally, the snap-fit connection is a mono-material connection, including advantages such as aesthetics, ease-of recycling or a homogenous thermal conductivity of the parts, which can reduce condensation and decay.

Photos : Claude Bornand et Violaine Prévost (IBOIS)
See also : Acadia 2014 Design Agency, USC School of Architecture, Los Angeles, edited by D. Gerber, A. Huang and J. Sanchez
Snap-fit joint research : C. Robeller, Y. Weinand, P. Mayencourt

prototype-bancs-weinand-2018
prototype-bancs-nabucco-weinand-2018