Walkway in Mungia (Bizkaia) Walkway in Mungia (Bizkaia) Walkway in Mungia (Bizkaia)

 
Walkway in Mungia (Bizkaia)

This footbridge connects the urban center of Mungia with the park of Torrebillela on the Butron river. The bridge presents a first peculiarity: it is really a circuit in a spiral that allows to solve the difference of dimension existing between the park itself and the street from which access is enabled in this area. The second and most relevant singularity is given by the fact that the said spiral circuit is defined on one of its sides as a cantilever up to 17 meters in length.

The strategy for the resolution of the cantilever passes through the use of the slope of the two inclined sections that define it for the formation of a large bracket. The key lies, then, in the difference in angle between the inclined sections, close to 15 °, but sufficient for the embedding of the cantilever or the large bracket to have a height close to 4 meters.

The described balance mechanism causes a mismatch or eccentricity between the laminar forces acting on the two key sloping sections, which in turn causes the transverse stiffness of the boards to be much more relevant than in a bridge problem common.