Architects Mario Bellini and Rudy Ricciotti have designed an avant-garde pavilion for the Louvre’s Department of Islamic Art in the palace's Cour Visconti. The Galleries for Islamic Art open to the public in September.
Together with the Cour Lefuel, the Cour Visconti is the most ornate of the Louvre palace’s interior courtyards. It was one of the few spaces at the Louvre still available for development and, until now, had remained inaccessible to the public.
Stunning yet conveying an understated elegance, Mario Bellini and Rudy Ricciotti’s design fully satisfies the aims of this public works project, through a play of contrasts. The design involves the creation of exhibition spaces over an area of 2,800 square meters on two levels, above another level devoted to technical facilities. As the focal point of this innovative architectural project, the new spaces in the Cour Visconti will be covered with an extraordinary structure, adding an element of surpassing originality, but one that does not detract from the beauty of the courtyard’s historical facades.
Following the restoration, from January to December 2006, of the Cour Visconti’s facades and statuary, under the direction of Michel Goutal, the Louvre’s senior historical monument architect, the courtyard was excavated to a depth of 12 meters. The resulting several thousand cubic meters of earth were moved through a single access point just 2.7 meters wide. The foundations of the facades were reinforced, consolidated and extended down to the bottom of the excavated area, by applying the jet grouting technique, which uses high-pressure jet fluids (400 bars) to erode the existing soil and then mixes the cuttings with cement slurry to form what is known as “soilcrete.” This technique made possible the extension of the pre-existing foundations down to the limestone layer, in order to proceed with earthwork.
The space thus created permitted the construction of two sub-levels: - a level devoted to technical facilities with a floating foundation suitable for the installation of the equipment controlling electricity supply, air compression, temperature, humidity and ventilation for the exhibition areas. - a parterre level with a foundation made of a single slab of reinforced concrete. The floor of the courtyard level is made of a composite steel and concrete structure, thus limiting the need for inconvenient columns breaking up the design of the galleries. An in-situ cast concrete staircase spans the 6 meters separating the first sub-level from the courtyard level.
On the ground floor of the new galleries, vertical partitions made of transparent glass allow visitors to look out on the courtyard’s facades. The use of glass without the addition of obtrusive metal structures ensures a clear vista. Each glass panel is about 2.40 meters wide, thus aligning perfectly with the pattern of the joins in the lead work. Panel heights vary from 0.5 to 6 meters.
Only low-iron or extra-clear glass materials are used, treated with iron oxides to avoid green reflections.
The brass-speckled black floor tiles echo the chromatic marriage between the golden tones of the glass roof and the black-colored self-compacting concrete of the walls. This muted atmosphere directs the visitor’s focus to the precious Islamic art objects displayed in these new galleries, in all their varying colors and motifs. The first sub-level is also inhabited by the vision afforded via the overlying structure thanks to glass openings in the floor of the courtyard level, reinforcing the unifying role of the unique luminous veil encasing the collection.
Visitors looking out from the surrounding galleries in the Louvre palace itself (Galerie Daru, the mosaic gallery on the museum’s upper ground floor, Salle des Etats on the first floor), will marvel at the undulations of the roof floating over this innovative edifice, giving the entire structure its poetic dimension.
Together with the Cour Lefuel, the Cour Visconti is the most ornate of the Louvre palace’s interior courtyards. Architecturally complex because its buildings were built in several stages, it does not offer a uninterrupted cornice on which a glass roof might have been easily installed. In addition, such a structure would have been situated more than one hundred feet over the collections and thus would have visually overpowered them. The solution selected by the winning architectural design team therefore proposed the creation of a sail-like glass and metal canopy set back from the historic facades on all sides (at a distance of between 2.5 and 4 meters).
Truly an architectural feat, this roof floats over the galleries in the manner of a golden, iridescent cloud, fondly referred to as a “dragonfly wing” by Mario Bellini. The supporting structure is comprised of a free-form double lattice system of round steel tubes all having the same diameter but of thicknesses varying between 4 and 12 millimeters, depending on the weight supported by the tubes. The luminous veil is formed of three layers: a system of glass panels, making the structure impervious to water, and two metallic mesh sheets fitted above and below the system of glass panels, bathing the entire roof in a bright and translucent anodized gold color. The exterior mesh filters daylight and the interior mesh serves as the ceiling for the galleries. The interior mesh is also lined with a honeycomb panel that, without limiting the amount of natural light getting through, restricts side views while favoring direct views of the outside, thus creating the play of contrasts characterizing the structure.
The three-dimensional geometry of this glass and metal skin required extensive computer modeling efforts, in order to determine the respective positions and angles of inclination for each of the triangles in the structure. The thickness of the canopy varies, as required by the supporting structure: thicker where it is fitted to the load-bearing columns and thinner at the edges, thus underscoring the undulating effect. The surface of the metallic mesh is composed of some 2,350 triangles, which when projected on a horizontal plane form isosceles right-angled triangles whose two equal sides are about 1.20 meters in length. The panels may be opened for maintenance purposes.
In all, a weight of no less than 135 metric tons rests on eight circular inclined columns. Four of them reach all the way from the glass-and-metal canopy to the second sub-level below and are up to 9 meters high. Svelte in appearance, their diameter never exceeds 12 inches.
To aid in the assembly of this gigantic nesting toy, each of the more than 8,800 pieces of tubing was identified with a reference number immediately after being produced by an automated machine in Slovenia, so as to ensure that each piece would take its precise position in the structure. Forty-five pre-assembled elements were transported to the construction site.
In the Krakow workshop where the framework was manufactured, then in Paris, during the final phase, the perfection of the assembly was verified using highly precise measurement methods. To address the specific challenges of this innovative and unique project, certification was obtained under an ATEx (Appréciation Technique d’Expérimentation) procedure, with the aim of testing snow load resistance, heating and dilation between glass panels and joins to guarantee their water tightness, as well as the resilience over time of the entire edifice. It was also critical to make sure that there were no points at which rainwater might stagnate, although some of the inclines are smaller than 10 degrees.
Mario Bellini and Rudy Ricciotti, the project architects, joined forces with the engineering design consultancy BERIM and with the structural design consultancy HDA (Hugh Dutton Associés) for the technical analysis of the glass roof and the facades, with 8’18” for the lighting design, and with Peutz for the acoustic design.