/ ABSTRACT
The viaducts over Zabaleta an Larrazábal streams and the Kinatoi viaduct are located on the section Elorrio – Atxondo, which is part of the HSL Vitoria – Bilbao – San Sebastián. Both structures support the double track railway of the Vitoria – Bilbao connection in the so-called Basque Y. The two viaducts have a continuous prestressed box girder deck, cast in place by means of a movable scaffolding system. Zabaleta and Larrazábal Viaduct has a total length of 566,0m, with a main span of 58,0m, whilst Kinatoi Viaduct has a main span of 65,0m and completes a total length of 880,0m. The present article describes the main characteristics of the two structures, as well as the construction sequence that was followed.