Pedestrian- and Bicycle-Bridge across the Central Station, Heilbronn
On the one hand, the bridge concept has to sustain its position within the heterogeneous urban environment limited by the two bridge heads and the railway tracks, and it has to provide the functional link between the central railway station and the new city district “Neckarbogen” on the other hand. Furthermore, is has to represent a landmark during the National Garden Show and subsequently.
Therefore, its design cannot solely follow premises defined by structural engineering, but has to underline a visual-emotional aspect which emphasizes the superior importance of this connection at any timer day or night, all year around.
The resulting composition is a dynamic and transparent “tube” which rhythmically enlarges its lateral dimensions beyond the required minimum clearance along its axis and thereby noticeably accentuates the long path across the bridge.
Out of the given situation of the railway tracks, a rhythmic structural system results with spans of 4 x 34,50 m and 1 x 13,50 m and a total length of the bridge girder of 151,50 m. The bridge head at each end is formed by a handicapped accessible elevator and a double-flight stair.
The bridge girder with a usable width of 4,50 m and expansions up to 6,50 m is conceived as a multi-span girder steel bridge with an orthotropic deck. The cross section is designed as a three-cell hollow box with a rounded lower surface.
The lower chord steel plate also used as a cornice is varies in its height from 100 mm and up to a parapet height of 900 mm. Guide grooves are embedded in the lower side of the hollow box in order to enable the erection of the bridge using the incremental launching method along the longitudinal axis.
By means of their own slenderness, the bridge columns will adapt to straining actions resulting from temperature changes. Without the use of any bridge bearing, a sustainable integral bridge structure with low maintenance costs will be realized.
The weatherproofing enclosure of the tube is realized by overlapping acrylic lamellas which are enabling a good ventilation of the tube, turning the route across the bridge into an extraordinary experience by changing transparent colors in a scale form green via yellow to blue.
The structural system of the enclosure tube is formed by a quadrangular geodetic net of equal mesh sizes consisting of crossing flat steel elements. The shell action of this stable net structure allows the formation of a cantilevering roof extending as far as 18 meters above the access stairs at the both bridge heads.
City of Heilbronn
Auer Weber Architects
3rd prize in competition (behind two 2nd prizes)