transitworks' parent company (GPO) provided planning, detailed design and construction supervision for the Sant Joan Despi-Sant Boi de Llobregat Segment, the first of four sections leading into Barcelona from the south. The segment extends 2.60 miles across several municipal districts in Barcelona province. The team worked with the client and affected parties to create a design that would be aesthetically pleasing, minimize environmental impacts and provide an appropriate gateway into Barcelona, Spain's second largest city.

The design features a unique viaduct that is 0.60 miles long and includes two clearly distinguished sections. The first section crosses the C 245 road and the second section spans the Llobregat River. The viaduct connects with a tunnel that extends through the Llobregat agricultural park and under several major arterial junctions. The 1.95 mile tunnel follows a curved route on a continual hill. Groundwater levels in the tunnel area necessitated shoring with a well point system to reach the deepest section. The use of a travelling formwork to conduct concrete work in the cut-and-cover tunnel section substantially reduced the time needed to complete the work. Special measures were employed during construction to mitigate traffic disruptions along the heavily travelled route and to maintain on-going operations at the agricultural park.