External prestressing in the footbridge of Museum of the Science in Valladolid

Abstract

This article presents the practice, development and technology applied in the external prestressing cables of this singular footbridge placed in Valladolid over Pisuerga river, being part of Museum of Science urbanistic complex. There are two prestressing cable systems, the hexagonal tendons and the longitudinal ones.
Hexagonal tendons have the property of having strong deviations in their layout, specific saddles were designed with low friction materials, and Freyssinet Cohestrand® was used. Real scale tests were carried out to develop these deviation devices. Hexagons stressing operations were carried out with two jacks simultaneously due to the section sensibility to non symmetrical efforts.
In longitudinal tendons, with little deviations each 7 m, external prestressing grouted before stressing system was applied, which allows strand by strand substitution. Geometry adjustment of these tendons required auxiliar strand disposition as a support of a regulation system.