PROJECT

In November 2018, Lausanne Cathedral hosted six performances of the opera Nabucco. For this specific event, IBOIS developed a new wooden scenography, which includes bleachers for the spectators (applying the principle of snap-fit wood-wood joints, see related article) as well as a five meters high wooden spiral in the center of the stage. This structure was composed of twenty-nine CLT 3-plys spruce panels boxes, which were screwed together and suspended by steel cables to resist the tension loads.

In order to define the exact dimensions of the project, the interior of the cathedral was scanned using Faro Model S 150. Thanks to this 3-dimensional model of the church, it is possible to accurately position the project, including the stands with a constant slope in the direction of the stage, and the spiral positioned at the center of the cathedral’s nave.

The use of digital fabrication and automation of the fabrication process was required, because of the precision and the uniqueness of every part of the structure. The 3D modelling algorithm was developed for creating box-to-plate assembly, depending of the initial inputs, such as cone height and width, the thickness of the panels, joinery (finger-joints), external connectors (dowels, screws.), assembly sequence and fabrication tool-paths.

The structural model was built in a Finite Element computational platform ABAQUS for analysis purposes. The FE model was then used for the design procedure, where the global stress values and the displacements were calculated. Following the different load cases, the structure demonstrated acceptable level of performance. Nevertheless, its global performance could be improved by changing its initial geometry.

4.5-axis CNC machine “Maka” was used for cutting panel outlines, drilling holes for screws and dowels, engraving panel indices and cable inlets. Furthermore, the G-Code tool-path was automated from design to fabrication within the same software interface. The whole cutting process took approximately two weeks.

SCIENTIFIC PUBLICATION

MORE INFORMATION

Project posters
Press release
Press review:
Le Temps – Nabucco
20 Minutes Lausanne – Des airs de Verdi à la place des cantiques
L’Agefi – Nabucco métamorphose la cathédrale de Lausanne
24 Heures Lausanne – L’EPFL et “Nabucco” transfigurent la cathédrale
24 Heures Lausanne – “Nabucco” brise les tabous à la cathédrale
Video:
RTS – Nabucco revisité dans une cathédrale de Lausanne aux airs d’opéra

PROJECT DATA

Location: Lausanne, Switwerland
Client: Amabilis (Renens, Switzerland)
Architect: Yves Weinand Architectes, Lausanne
Timber Engineering: Bureau d’étude Weinand (Liège, Belgium)
Technological transfer: IBOIS EPFL, Prof. Yves Weinand, Dr Petras Vestartas, Martin Nakad, Loïc Pelletier