The Abetxuko bridge over the Zadorra River in Vitoria is intended as a metaphor and a vindication of an open and creative engineering design which meanwhile does not exclude the more traditional vision of an analytical and pragmatic design. The design of the truss is intended as a deliberate diversion from the traditional straight forms and uses curves with an apparently arbitrary elevation. The irregular, curvaceous forms of this bridge are in defiance of the traditional use of symmetry, purity and order in engineering design.
The bridge is a continuous structure with three spans of 85+131+85 ft (26+40+26 m) and with a total deck width of 103 ft (31.4 m). It accommodates four road traffic lanes, a central tramway line with two tracks, and two pedestrian walkways.
The structural system consists of two parallel trusses with organic forms, their dimensions adjusted according to the structural analysis.
Fabrication of the complex steel structure was carried out at the steel shop in Vitoria. The process included preparation of drawings, definition of the pieces, cutting, preparation of plate edges, bending of curved plates, pre-assembling, welding of stiffeners, assembling of the segments, transport to the site, and the erection of the sections and welding of the rest of the steel members. The process of fabrication illustrates the enormous possibilities available through Cad/CN techniques. As the inner surfaces of the steel structure will be inaccessible, the members were made completely watertight.
Sobrino, J.A.; “Aesthetics of urban steel bridges”, Modern Steel Construction, AISC Magazine (ISSN 0026-8445), pp 52-55, March 2012.
Sobrino J.A.; “Abetxuko Bridge over Zadorra River in Vitoria” (in Spanish Puente de Abetxuko sobre el río Zadorra en Vitoria), Cauce 2000: Revista de la ingeniería civil (ISSN-0212-761X), n 139, pp. 74-77, 2008.