THE MIRAMAS ATHLETICS HALL: AN EXCEPTIONAL STRUCTURE

.Opened in the first half of 2018, the Miramas Métropole Stadium has already hosted several national and international athletics competitions. On 16 and 17 February, the French Elite Indoor Championships will take place, qualifying for the European Indoor Championships to be held in Glasgow in early March. This is another opportunity for the Stadium to showcase its many qualities, recognised and praised by athletes and spectators alike.

A unique facility in the south of France, the Miramas Métropole Stadium is one of the largest covered athletics halls in Europe and the only one in the Mediterranean Arc, between Genoa and Barcelona.
This facility was planned at the initiative of the French Athletics Federation and was built by the Ouest-Provence new agglomeration syndicate, which has since become the Istres-Ouest-Provence Territorial Council. It was created within the Aix-Marseille-Provence metropolis, which is now the project manager. This space completes the sports centre of Les Molières, already equipped with a stadium and an aquatic centre. It has been designed to host the world’s biggest competitions, team sports matches and, thanks to the modularity of its spaces, various shows.
Carried out under a design-build contract won by Travaux du Midi, SMC2 and Chabanne, the project brought together the complementary skills of the various players involved:

• Travaux du Midi, a subsidiary of VINCI Construction France historically based in Provence, coordinated the design and carried out the civil engineering work, the construction of the stands and tracks, the construction of the external works, the technical trades and the finishing work;
• The architect Chabanne, a specialist in the design of complex structures, who designed this large-scale facility;
• SMC2, a specialist in the design and construction of sports facilities with a wooden structure and textile roofing, which carried out the framework, façades and roofing;
• The Serge Ferrari group, which advocates an economic and ecological approach, wove and coated the high-performance composite membranes that combine flexibility, lightness, translucency and great resistance.

An architecture of movement designed for international competitions

“The kinetic and faceted architecture of the hall offers an attractive and contemporary image of athletics, marked by dynamism, movement and vitality,” says the architect. Complemented by a 67 x 25 metre gymnasium, the 130 x 82 metre hall appears as a large volume, both massive and aerial, characterised by its white pre-stressed fabric roof which shapes its silhouette. It houses a 200-metre circular track with 6 lanes, a 60-metre central track with 8 lanes, 2 pole vaults, 2 long vaults with triple jump, a high jump, a mobile shot put workshop and 110-metre warm-up tracks installed under the stands. Its approval by the IAAF (International Association of Athletics Federations) implied particular technical and dimensional constraints which, as Carole Martin, Director of Activities at Travaux du Midi, points out, impacted on the construction processes: “The bends of the central track are inclined to the millimetre and its surface is the most efficient in the world.”
Connected to the hall by a glassed-in interior street from which one can enjoy the spectacle of the sports activities taking place on either side, the gymnasium is used for the practice of team sports – basketball, handball, volleyball, etc. -, dynamic sports and training for athletes.
Depending on the type of event, the capacity of the stands and the floor varies from 5,500 spectators in an athletics configuration to 7,500 in a team sports or entertainment configuration.

The combination of several materials for a unique building

The athletics hall is structured by a glued laminated timber frame consisting of lattice girders, triangulated purlins, crossbeams and bracing elements assembled with steel parts to form more or less complex joints. The 12 gantries of the hall, anchored in a concrete base, span 82 metres without intermediate support in order to free up as much space as possible.

The teams achieved this technical feat with the help of Building Information Modeling (BIM), a 3D modelling method that provides a global vision of the building and all the elements provided by the project’s stakeholders, and allows the construction to be phased.

The use of wood in the framework of sports buildings is a real eco-responsible alternative to more traditional solutions such as steel. By storing CO2, wood has undeniable ecological qualities that help combat global warming.

The use of a double membrane to cover the competition hall provides protection from the weather, filters UV rays and, unlike other systems, provides even light without glare and shadow-free illumination, ideal for competitive athletics. It also offers excellent acoustic and thermal qualities, for optimum comfort for both athletes and spectators. As Laurent Tournié, Serge Ferrari’s business manager, explains: “The appearance of Flexlight Xtrem TX30 fabric is very durable thanks to the Crosslink treatment. In addition, the prestressing ensures great dimensional stability for this very homogeneous product under tension. Guaranteed for 25 years, its durability is estimated at over 40 years.”

The membrane used for the facades has been the subject of a technical assessment of experimentation (Atex) issued by the CSTB, in collaboration with the control office Qualiconsult.
The Miramas Stadium is, to date, the largest stretched fabric building in Europe. This work makes its various contributors and the local players proud, as they now enjoy a modern, elegant stadium, ready to welcome high-level athletes and to serve their sporting ambitions. Nicolas Robin, Managing Director of SMC2, is delighted: “We wanted the Stadium to illustrate the challenge that sportsmen and women take up when they put on their boots. To always do better, to always see further.”