Bridge over Po river in Piacenza: A never before seen structure
Autostrada del Sole
Gambellato and Merizzano overpasses:
Giulio Krall’s two "little" jewels
GAMBELLATO OVERPASS
Engineer: Giulio Krall
Engineering firm: Ferrobeton
Span: 124 m
Material: reinforced concrete
Year of construction: 1957-1960
Site: Castiglione dei Pepoli (BOLOGNA)
Static scheme: single big arch
MERIZZANO OVERPASS
Engineer: Giulio Krall
Engineering firm: Ferrobeton
Span of each arch: 87 m
Material: reinforced concrete
Year of construction: 1957-1960
Site: Castiglione dei Pepoli (BOLOGNA)
Static scheme: two arches
Giulio Krall’s initiation, who at the time was Ferrobeton’s technical manager, occurred during the economic boom with the construction of two bridges for the stretch of the Autostrada del Sole between Florence and Bologna: the viaduct over the Gambellato and over the Merizzano.
Initially, Francesco Aimone Jelmoni, designer of the entire industrial plan, had conceived three parabolic arches for the first overpass; Krall, however, decided to discard this idea in favor of a much cheaper one that consisted of a single big arch with an optimized shape that could respond better to the various stresses, in support of the pillars that uphold the road deck.
The second overpass has a clearly visible frame and its structure is very similar to the one of the
Gambellato overpass, but with one difference: it has two arches instead of one.
Even here, both construction sites were dominated by the Innocenti scaffolding, laterally shifted throughout the construction of the Gambellato, but dismantled and reassembled four times for the arches of the Merizzano, due to issues with the resting ground; in fact, the ribs of the ditch were very steep and the sliding surface for the supports could only be obtained at the bottom of the valley.
Works, contracted to Ferrobeton in 1957, were completed in 1959 and tested in 1960.
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