S. Miguel, Azores, Portugal
The Viaduct over the Achada Stream is located in the 3.1 Stretch – Barreiro/Algarvia of the Expressway Concession on S. Miguel Island already mentioned in this publication. The particular character of this project is the insular nature of the Island, that results in a relocation of an unusual set of technical and human resources as well as materials, specific to the construction works, which, in some cases can take weeks, as they are transported a long way by sea, forcing an intense and insightful planning . Another particularly important feature is the volcanic origin of the island, which is translated into a very specific geomorphology caused by very heterogeneous and complex geological structures , shaped by rock formations, associated with volcanic activity, interspersed with each other, and covering layers, often unstable, consisting by deposits of pyroclastic, alluvial or landfill nature. The structural solution is the same described for the Viaduct over the Caldeirões Stream resulting in 3 spans and a total length of 192,2m between abutments, comprising a middle span of 93,6m and 2 side spans of 42m and 56,5m at the west and east side, respectively.