Associate - Project Manager - Construction works supervision and management - Civil Engineer
PortBrügg bridge and tunnel portal
This bridge crosses the Nidau-Büren canal, and spans over a hydro-power station and a waterway lock. It is located beside a water regulation system from 1936 used to control the water level in the canal. The challenge of building a new bridge beside a heritage structure was resolved by differentiating the two structures.
The bridge has a cable-stayed design with a single central tower supporting the deck with a single cable series. The harp-style cable arrangement creates a sculptural vision of the structure while also being highly effective for static purpose. The tower rising from the canal is the sole point of contact with the waterway. The impact is thus minimal, and, for hydrodynamic reasons, the tower is aligned with one of the existing piers of the water regulation structure.
The bridge movements are free, and the only fixed point is at the tower. The cable stayed spans are 84 m and 86 m either side of the tower. An additional pier is added on the Brügg side to extend the deck to the abutment. Sliding bearings are fitted on the Brügg side pier and on the abutments where maintenance is easier.
The deck has a constant height of 1.50 m and a width that varies from 17 m to 19 m. It is made from solid concrete to provide high rigidity and durability. However, to reduce its weight, it is carved and hollowed throughout its length creating struts in the side sections.
The bridge deck is constructed with the balanced cantilever method allowing to maintain the operations of the hydro power station and the lock during construction.
On Port side, the bridge adjoins a tunnel with a portal formed by the intersection of retaining walls progressively entering the ground. The portal lintel is supported by these walls and the connection is made by triangular-shaped walls. The whole forms an integral portal, creating the transition from the plain to the hill, the bridge and the tunnel.Share