As a new urban belt was to be built, we got the commission for the design of this crossing over the Pisuerga river, in which we regarded an opportunity to improve the urban quality of the South districts of the city.
The result is an urban cable stayed bridge with a quite special design, consisting mainly in two triangular elevated concrete frames which combine a compressed mast and a tensile stressed inclined “sail” that give rise to a carefully designed concrete “head” where the fan of stays is born. The organization of the 30 m wide deck consist of two longitudinal concrete hollow-box girders, 25 m apart in the transverse direction, supporting a series of transverse steel trusses spaced every 9 meters. Over this arrangement a set of longitudinal concrete top slab of 18 cm thickness is placed.
The main span of 120 m, flies over the Pisuerga, while the lateral counterweight span is 36 meters long. Its construction procedure was based on free cantilevering. The prestressed “sails”, conceived to substitute the classical backstays, reduce, thanks to their increased axial rigidity, the maximum bending moment in the main span due to live load to about one fifth of the bending moments arising with the classical backstays.
The frames constitute concrete sculptures marking the entrance to the South districts of Valladolid. The bridge creates an architectonical space that is clearly perceived by the passerby. Somehow, this public work approaches the idea that concrete structures should have a minimum aspiration to become useful art.
