Ring at Level 40

This road located in Funchal, circles its Centre at a level close to 40 m. In order to allow for a continuous flow of traffic there are no semaphores and all crosses are built at different levels. A roundabout located in the Largo da Cruz Vermelha, ensures the link with the other arteries in the city. This stretch has a total length of 750 m, of which 160 m are built in tunnel, 140 m in a concrete domed gallery (built at open sky), and 80 m in a portico gallery capable to support a five storey building. The works also included the construction of two overhead crossings over the ring. The excavation works for the tunnel construction included also the use of explosives. The process was closely monitored by seismographs and minimal explosive charges were used, due to the existence, in the vicinity of the works, of a Monastery and a Library both classified as national monuments, as well as of several old buildings over the tunnel. Also the low thickness of layers over the tunnel posed major constraints to the development of the works. The final revetment is made of projected concrete being the supporting structures in armed concrete. The domed and portico galleries in armed concrete have been built in open sky, with vertical embankments reaching a height of 11 m.