PSI - Issue 62

Irene Matteini et al. / Procedia Structural Integrity 62 (2024) 738–746 Matteini / Structural Integrity Procedia 00 (2024) 000 – 000

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Figure 3 (a) Engineer Gustavo Colonnetti (Courtesy of Polytechnic of Turin); (b) Patent n. 383586, G. Colonnetti Trave armata ad armature preventivamente tesa, 1939 (Courtesy of Archivio Centrale dello Stato).

The first true application of prestressing in Italy were carried out on concrete pipes. Manufactured by Vanini, these prestressed concrete pipes were made by spirally wrapping and weaving a steel wire around an already cured pipe, and then protecting it with a layer of fibre-reinforced concrete (Italian Patent n. 314685 by Guido Vanini & C., 1933) (See Figure 4). With this patent, Vanini claimed the rights to a machine that was capable of prestressing pipes using steel wire under tension. Few years later, in 1939, the S.C.A.C., Società Cementi Armati Centrifugati, further developed its already famous centrifuged concrete poles by inserting tensioned high-strength wires along the length.

Figure 4 (a) Patent n.314685 by Guido Vanini (Courtesy of Archivio Centrale dello Stato); (b) Italian Patetnt n.375161 by Società Cementi Armati Centrifugati SCAC (Courtesy of Archivio Centrale dello Stato).

However, the first patent on prestressing concrete beams is attributed to Eng. Colonnetti, who developed a new innovative method for the calculation of partially prestressed beams (Figure 3) patented in December 1939. This patent blended the best aspects of the systems previously developed by E. Freyssinet himself and, in Germany, by Franz Dischinger (Marro, 2011). Despite Colonnett i’s great effort and enthusiasm for this technology, the implementation of prestressing in Italy delayed a few more years, primarily due to the unavailability of high strength steel caused by the war.