SWITZERLAND

Italian bridge over the river, Chur

Plessur Brilliant solution of elegance and lightness

Laudatio: The filigree bridge structure fits the urban landscape well, is technically challenging and very lovingly detailed. This brilliant solution of elegance and lightness feels as if it always has been there, making the life of pedestrians and bikers not only easier but also beautiful.

The city of Chur has built a new bicycle and pedestrian bridge over the river Plessur making it easier for non-motorized traffic to pass through the old town. Due to the given locations of the abutments a 77 m long bridge was necessary to cross the 14 m wide riverbed.

Concept

The new steel bridge consists of an S-shaped curved bridge girder supported by ropes that are attached to a diagonally arranged arch. The horizontal curvature of the girder creates a spatial distance to the river banks. On the one hand, structural measures as well as restrictions of the sight to the historically significant fountain garden park are minimized on the right bank and on the other hand, a distance to the building facade on the left bank can be achieved. Thanks to the slender bridge girder and the lightsome railing, the sophisticated structure of the bicycle and pedestrian bridge fits perfect- ly into the demanding historic town.

Structure

Arch and girder are the main structural elements. Because of their curved shape both are monolithically connected to the abutments. Constraint forces due to temperature are transferred with micropiles into the subsoil. Lateral stabilization of the arche is achieved with the rigid fixation and the inclined ropes.

Fabrication & Erection

The girder was delivered in four and the arch in three sections. A temporary assembly platform with support towers was necessary. Installation was mainly done from left bank. Two steel components of 20 and 32 tons were lifted with a medium-sized mobile crane. Lifting of the re- maining five steel components with 17 to 32 tons required a large mobile crane. The steel components were welded together and the ropes installed with initial shortening.

Sustainability

The elimination of expansion joints and bearings leads to a durable and low maintenance bridge. A total of 170 tons of structural steel S355 J2 was used to fabri- cate the bridge girder and the arch. The durability of the steel components is ensured for corrosivity category C4. For the construction of the two abutments, a to- tal of 430 m3 reinforced concrete and 540 m micropiles were used.