We have built the only cable-stayed high-speed viaduct in Spain 

A joint venture led by Sacyr has built a singular infrastructure in the Hernani-Astigarraga rail section: an impressive 482-meter viaduct. 

In 2019, the Basque Railway Network awarded the construction project of the Hernani-Astigarraga Phase 2 section platform to the joint venture Hernani-Astigarraga - Sacyr Construcción (60%), Sacyr Neopul (10%), Mariezcurrena (15%) and Zubieder (15%).

To develop this 2.4-kilometer section, we had to build a cable-stayed viaduct, among other infrastructure, that crosses the Urumea River twice and passes under the A-15 highway. 

The installation of the last cable stays will take place over the next week. 

The viaduct is 482 meters long and allows to cross over the Urumea River through two cable-stayed sub-structures with maximum spans of 67 and 120 meters.



108 braces across the three metal masts are necessary to support the board which is 14.5 meters wide and has a variable edge of up to four meters.

In just a few weeks, this viaduct will be completed, with only the task left to connect it to the third rail track that will reach Atocha station. This will allow the railway platform that serves as an access for the high-speed rail train to Donostia-San Sebastián to be ready in a year.

20,000 m3 of concrete

Over 20,000 m3 of concrete and 4,000 tons of steel have been used to build this structure. Since the section is U-shaped, it will have a usable width of 10.7 meters to accommodate the plate track and gutters.

The three masts are made of S355 and S460 structural steel and are 27-meters high. The deep foundations have been made with piles that have reached a depth of more than 40 meters. 


Innovation to identify improvements

This project is particularly noteworthy for the wide range of special techniques that were required for its construction. From executing deep foundations, to terrain improvement treatments have been executed under innovative techniques that have added value to the project.

In addition, a complete 3D model of the entire project was created to allow to identify and anticipate errors, as well as suggest optimizations and improvements.  

A project with a marked environmental character

The entire project is framed within the terrestrial maritime public domain area defined by the bank of the Urumea River, which gives it a marked environmental character. As a result, relevant actions have been carried out, which include:  

* The management of 16,807 tons of polluted soils with organic compounds and heavy metals using ex-situ techniques.
* The treatment to avoid the proliferation of native vegetation through the removal of 9,000 m2 of invasive species by mechanical means. Invasive species represent the second greatest threat to biodiversity, after the loss of natural habitats.



Penultimate stage

The Hernani-Astigarraga section is the penultimate to be carried out of the 18 awarded by the Basque Government. Thus, only the Astigarraga-Lezo section is left for completion, which is currently under informative study.

In the capital of Gipuzkoa, work is underway on the future new station, which will be ready in a year and a half. Thus, the HSR access railway platform in San Sebastian is expected to be complete in Spring 2024.

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