Charles Nègre media library, Grasse

Text by Laurent Beaudouin. “The Grasse media library is inspired by the character of Grasse’s urban structure, the tensions and proximities between the buildings. As a counterpoint to this density, the media library offers visual openings onto the neighbourhood and the distance. The project uses the presence of programme elements with a certain independence to create several levels of access. At the bottom of the site, the hall on Rue Droite serves as a common foyer for the exhibition room and the auditorium, and an open arcade in an existing building improves the passage to Place Vercueil. This square is intended for the installation of restaurants and provides access for service vehicles. The square is connected to the Rue de la Lauwe by a pedestrian walkway along the water reservoir that supplies the city, opposite the exhibition hall. The media library is partly cantilevered over the old reservoir.

This layout is the basis of the static diagram for the new building.

The horizontal stability of the building is achieved from the centre by the reinforced concrete walls of the stairwell and lift shafts as well as by the independent, thick transverse walls. The addition of the latter allows the vertical axis torsion resulting from the seismic action to be limited.

The transverse walls and cores are embedded in the substructure and function as brackets like “masts”. As the bracing is not symmetrical and is also eccentric to the centre of gravity of the building, particular attention is paid to induced torsional effects.

As the action of the earthquake can be assimilated to a fraction of the horizontally applied self-weight, the horizontal “vault structure functioning as beams” allows the self-weight of the primary structure to be optimised and consequently the associated seismic force to be reduced.

The existing structure, which has been preserved, has been the subject of a seismic reinforcement study which allows the typology to be preserved while improving the overall rigidity and the foundation on the existing ground.