The ground decided the design. On the slope that the Sicignano-Potenza motorway connector had to cross, soil conditions ruled out planting piers, so Riccardo Morandi went over it in a single opening of 181 metres between the pylons. The Carpineto viaduct, or Carpineto I, is not a single bridge either, but two identical cable-stayed bridges side by side, one for each carriageway of the RA 5, two lanes apiece.
What to see
The pylons, 29 metres high, are what you notice from a distance, and they lean. The load bears on one side only, so the pull is not balanced above the pylon as it is in symmetrical cable-stayed bridges: the pylons tilt outwards and are anchored back. The anchor blocks are about 16 metres long and stay in the ground, held by horizontal concrete bars 12 metres long resting on the pylon foundations. It is a structure that declares how it works: you can read the whole of it standing still and looking.
The two bridges are identical to each other and unbalanced in the same way, so the pylons come in pairs, one pair per carriageway: that is the outline that makes Carpineto recognisable before you reach it. When it was built, the technical journal L'Industria Italiana del Cemento devoted two articles to it, in 1977 and in 1978, under the name viadotto Carpineto 1°.
Visiting
This is a working piece of infrastructure, not a site open to visitors: you drive over it on the RA 5, in the territory of Vietri di Potenza, and the crossing lasts a few seconds. At the wheel you notice it only by the stay cables running past the window; the shape of the bridge can be seen only from outside, from the slope it steps across.
Our editors' tip
Line it up with the Platano viaduct, on the same road and in the same municipality: they are two opposite answers to the same problem. Morandi hangs the span from stay cables and pushes the pull down into the ground; Zorzi and Procaccia, at Platano, prop two struts against the sides of the gorge instead. See them on the same trip, in that order, and you will understand why the RA 5 is a small anthology of the Italian engineering of those years.