18.053

R0 Timber Footbrigde

Belgium

Tervuren

Context

As part of the optimization of the R0 East ring in Brussels, a comprehensive set of measures is being developed to promote sustainable mobility. One such measure is the construction of a footbridge over the Vier Armen junction in Tervuren. This bridge will provide a direct connection for cyclists and pedestrians over the high traffic lanes. Located in the Sonian forest, this new timber footbridge is 67.5 meters in length. The selection of wood for this project was not solely for aesthetic reasons, but also to take advantage of its structural properties, which were fully integrated into the structural design.

Particularities

The bridge design features an innovative pentagonal box girder structure with G-LVL panels. A variation in structure height, ranging from 5 to 7 m above the bridge deck, allows a low deck height to enhance cyclist comfort. The bridge deck itself is 6 m wide. The footbridge’s structure is composed of glued LVL panels, which were used for all the main structural elements. These panels are made of 2 to 7 layers of Kerto Q (from Metsäwood), resulting in a final thickness of up to 22 cm. The thickness of each panel has been carefully optimized to match the specific forces it will encounter. The cross section of the footbridge combines a deck, facades, and roof panels, which are joined by a series of inclined screws to transfer shear forces between each panel. Transversal LVL frames, placed every 3 meters inside the bridge, ensure lateral stability. The footbridge incorporates two steel portals at each end, which transfer these forces to the supports, enhancing the overall stiffness of the structure.

Given the bridge’s considerable span, it was divided into six segments, each no longer than 12 meters to comply with conventional transport limits. The segments were prefabricated on the ground near Tervuren Avenue, about 800 meters from the final installation site. The segments were joined using embedded steel plates and dowels, with special attention paid to creating moisture-resistant connections to ensure long-term durability.

To protect the wooden structure from environmental elements, the bridge features an extended roof made of aluminum panels that shields the structure from rain at a 45° angle. Construction was strategically planned in six stages to ensure that the wood was quickly covered and protected from water stagnation. This methodical approach significantly enhances the longevity and maintenance of the bridge.