With the wooden bridge over the A1 highway, the Société de livraison des ouvrages olympiques (SOLIDEO) has created the gateway to the 2024 Olympic and Paralympic Games. More precisely – the connection between the media village in Dugny and the sports and school park in Le Bourget. The planning and construction was carried out by the engineering firm Miebach from Lohmar and AIA Life Designers in collaboration with Explorations Architecture. The bridge remains as a permanent crossing and improves the connection to the Parc Georges-Valbon, the third largest green space in Île-de-France.
The 100-meter-long bridge is a special feature in French bridge construction. Wood is rarely used there for large engineering structures. The engineering firm Miebach from Lohmar contributed its expertise to the project and worked together with the French engineering firm AIA Life Designers. Together with Explorations Architecture, they won the competition for the bridge construction in 2020.
The structure consists of a three-span beam bridge with a stepped supporting structure made of block-bonded glulam. The deck was made of precast concrete elements, the railing of architecturally shaped round steel, the handrail is made of steel. A total of around 330 cubic meters of glulam made from French Douglas fir was used.
Despite widespread preconceptions about the durability of wooden bridges, load tests have shown the high resistance of the structure. The bridge was designed to withstand a two-hour fire on the highway below. While steel loses its load-bearing capacity when exposed to heat, wood forms a protective carbonization layer that preserves the inner structure. The architectural design also ensures a high level of structural timber protection. A 30 centimeter protruding concrete edge and beam edges inclined at 30 degrees protect the wood from direct rain.
The design of the bridge is both minimalist and sculptural. The shape is inspired by the minimal art of the artist Carl Andre. Two inclined pillars lend the structure dynamism and make it stand out from the wooded surroundings. The lines in the ground plan and elevation were designed with particular care to create harmonious proportions. Another model for the construction was a wooden bridge in Neckartenzlingen, Swabia, which was also realized by IB Miebach. There, too, the appearance is characterized by an inclined support.
In line with the sustainability goals of the Olympic Games, the bridge was designed with a particular focus on the carbon footprint. The timber construction significantly reduces the carbon footprint compared to conventional materials. The Douglas fir used comes from sustainably managed forests in the Morvan region of France.
Concrete was only used for the foundations, pillars and abutments. A light-coloured road surface minimizes heating from solar radiation, while the intensive planting in the surrounding area reduces the phenomenon of the urban heat island. Excavated material from other Parisian construction projects was also used for the backfill. The total CO₂ footprint of the project is 1100 tons of CO₂ equivalent.
The wooden bridge in Paris is an example of a construction method that takes aesthetic, functional and ecological requirements into account. It connects city districts and improves access to green spaces. The structure demonstrates the possible uses of wood in bridge construction and serves as a reference for sustainable constructions in urban areas.
In our May 2024 issue, we made an issue about bridges. You can find the magazine here.
