Bridge over Po river in Piacenza: A never before seen structure
Autostrada del Sole
Bridge over Po river in Piacenza: A never before seen structure
Engineer: Silvano Zorzi
Engineering firm: Rizzani
Length: 1200 m; 16 spans 75m each
Material: prestressed reinforced concrete (BBRV patent)
Year of construction: 1957-1959
Site: Piacenza
Static scheme: simple beams
The construction of this overpass, located along the highway section between Milan and Bologna, represented the first major application of prestressed reinforced concrete for the Autostrada del Sole, and was also rated as a huge milestone throughout Europe, at the time.
The 3.2 m high beams, made of prestressed reinforced concrete, lean on ordinary reinforced concrete piers that are covered so as to seem made in brickwork. Once the casting was done, when the cement would start to harden inside the formworks placed over the piers, the very resistant steel wires, that form the cables dipped in the conglomerate, were tenesed with a jack.
Once again, the main character on site was the Innocenti scaffolding, assembled like a folding fan to cover even large spans with few elements and poetically defined "a wonderful frame of tubular steel trestles".
Even this time, the swinging derrick Cruciani Blondin was amongst the preferred construction items because it would allow a distribution of the casting for the launching of the beams and for the form
dismantling thanks to a suspended cables system.
A tank-proof bridge
For the first time, Rai's cameras, along with those of the Istituto Luce, were also present on construction sites and began broadcasting images of the construction that was taking place, until the completion of the last span, finished 2 months in advance! Up to that moment, in fact, there was no awareness in Italy of what was happening and even the cities that were directly involved had no idea of where the highway would head.
Finally, for the test, carried out between June 4th and 5th 1959, the overpass was crossed by 20 fully loaded trucks and 10 "Patton" tanks 44 tons each; this operation was the final confirmation that the bridge could safely cross one of the most critical and indomitable rivers: the Po.
Listen to the recording!
