Théâtre Marigny in Paris, France

The panorama, built in 1881 by architect Charles Garnier, the architect of the Opéra Garnier, changed to serve as a theater ("Les Folies Marigny") in 1893 with 1,200 seats by architect Edouard Niermans. In 1925, the theater was renovated under the new manager, Léon Volterra: The exuberant decoration of Niermans was removed and only the original form of the building, a dodecagon with a diameter of 108 ft, was kept.

Architect Alvaro de Grimaldi designed the current hall, inspired by the Art Déco movement with a neo-Pompeian tendency. A new hall was built in the foyer in 1980.

Renovation Project

Before the renovation, the theater roof showed severe defects. Therefore, the building was closed in 2013. The metastable equilibrium resulted from unreliable planning, which did not consider the effects of an asymmetrical load and suspended ceiling on the roof structure during construction in 1925.

Due to the preservation orders, it was impossible to remove the roof completely. Therefore, only interventions inside the roof were possible.

The project of renovation and reinforcement consisted primarily of:

• Separating the roof and ceiling constructions. It is suspended on a new glued-laminated timber construction, supported by steel members.
• Adding new stiffening for the existing structure, consisting of new glued-laminated rafters, supported by prestressed cables.

To reduce the horizontal pressure, elastomeric bearings (elastic) were introduced between a metal ring to distribute the loads of the two structures on the concrete-cast downstand beams onto the 12 masonry pillars.

Structural Planning

The design of the new structures required extensive planning of the construction process (based on 3D sketches and modeling of the existing buildings with Revit) and calculations with RFEM and the add‑on modules by Dlubal Software.