Line 9 is a part of the Barcelona subway network that is currently under construction. Upon its completion, it will be the longest automatic subway line in Europe. The total system will have a length of 47.8 km, of which 43.71 will be underground and 4.09 on viaducts. L9 will be the deepest line in the Barcelona network.
Many different redesigns have been performed to improve their constructability and structural design, mainly in the stations Gornal, Torrassa, Collblanc, Campus Sur and Zona Universitaria. All of them have a similar configuration: they are cylindrical with 18 m diameters in plan view and more than 40 m deep. Most of them include links with other existing subway stations.
The stations were built by top-down construction method. Horizontal perimetral concrete rings were made at each stage. For the first time in Spain, shotcrete was the construction technique adopted to make these reinforced concrete rings.
Complex 3D analysis models were necessary to take into consideration loads and geometric asymmetries. Secondary elements, such as platforms, openings and connection passages under existing roads under service, among others, were also redesigned to minimize interferences with traffic, effects to existing facilities and buildings, and also to optimize structural elements.