“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 work carried out on the Mondariz Bridge over the Xabriña river is detailed. During the Main survey, several pathologies were detected in the structure that forced the traffic to be cut off. Following an exhaustive testing campaign and structural modelling, the repair and strengthening measures for the elements requiring intervention were designed.”

“The work carried out on the Santa Marta Bridge, over the Umia River, is detailed. The former bridge crossed the river with an intermediate metal arch with a lower footbridge hanging from it.”

“It is considered important to make a separate paper on the construction of the viaduct due to all the obstacles encountered during the process, being an arduous, long and much more complicated task than a bridge of similar characteristics."