Line 9 is the longest and deepest line of the Barcelona subway network. As of 2020, the line is already operational in 24 of the total 39 planned stations. Upon completion, it will be the longest automated subway line in Europe. The total system will have a length of 47.8 km, of which 43.7 km will run underground and 4.09 km on viaducts.
Pedelta participated in the structural redesign of five stations on this line to improve their constructability and structural design. The five stations are Gornal, Torrassa, Collblanc, Campus Nord and Zona Universitaria, of which four are operational since 2016. All of them have a similar configuration: they consist of cylindrical shafts of 18 m in diameter and more than 40 m in depth. Most of them include connection facilities to 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 in service, among others, were also redesigned to minimize interferences with traffic, impact on existing facilities and buildings, as well as to optimize structural elements.