Dalla Liberazione alla Ricostruzione. Storie di ponti

The war that led to the liberation of Italy was fought to regain territory inch by inch. The road and rail networks were strategic objectives for both sides: the troops who were retreating and those who were advancing. Thousands of bridges were damaged and destroyed, tons of iron, bricks and concrete collapsed into the rivers. The “first aid” given to the structures, led by the Allied Corps of Engineers, was based on salvaging what could be saved. With improvisation, intuition and courage the “standard” procedures of the American manuals combined forces with the experience of the Italian artisans.“Surgical” interventions were made on the structures that had been bombed or blown up: hoisting, cleaning up, and rendering unusual combinations of materials and structural schemes. There was a cross-fertilization between the American method and the “know-how” of the Italian technicians. In the Sappers’ language, new words appeared like “structuring” and “centering” (used to codify unusual procedures for stabilizing viaducts standing on masonry arches or the use of emergency ribs to support the most damaged arches), for which an appendix entitled “Unconventional methods” was added to the manuals. They contained descriptions of how to improve materials by using “salvaged” items; and detailed descriptions were made of unorthodox bridge launching procedures, like the “Italian style incremental launch” (where a “train” of beams are launched by stiffening the head beams to avoid the need to set up temporary noses). The reconstruction that followed after a few months, made possible by US economic aid, was an unprecedented feat for Italian engineers and construction companies. The railroad network had to be reinstated and the roads upgraded to keep pace with the economic recovery of the country. This is how the bold solutions tried out in the previous years came to maturity in a collective professional spirit. While the National Liberation Committee took on full powers, the front lines, abandoned by the Allied troops, were enlivened by new opportunities. Companies submitted bids for the tenders issued by the Ministry for Public Works with great enthusiasm, calling on engineers to cooperate with them. For engineers, this was the opportunity to demonstrate their technical skills and ability in the execution of construction work. There were cost constraints (funds still came through the Allied Military Government), a shortage of plant and equipment and steel was still requisitioned by the military. Cement was the only material for which the Allied Government could ensure supplies. These were the conditions surrounding the “counterbalanced” beams used by Riccardo Morandi over the river Liri, and for the “Maillart” arches by Arrigo Carè and Giorgio Giannelli over the river Nera and over the river Frigido, the “steelless vaults” by Carlo Cestelli Guidi over the river Arno, and for the “rotating semiarches” by Giulio Krall on the river Calore. When the Republic was proclaimed in 1946, activities began for rebuilding the towns and their bridges. Here cost constraints and limited equipment were compounded by the special need to comply with “stringent aesthetic criteria”: Morandi and Krall, respectively in Florence and Pisa, designed two low-rise arches in reinforced concrete, “to provide a frame though which the hills and the town would be seen ... in harmony with the monuments”. The final reconstruction of the bridges over the Po River was started. This was an enormous collective endeavour, where everyone’s collaboration was needed. In Piacenza, the Dalmine company signed a unique proposal for the assemblage of steel tubular trusses with huge savings on materials. In 1948, with the launch of the Marshall Plan, the 300 billion lire of revenue raised from the sale of goods from the United States, and entered into the State budget under the item Fondo Lire, constituted the basis for funds available on request to municipalities and companies. Infrastructure was the heart of the Plan for the economic recovery of the Country and was the means for physically receiving aid at the local level. This “new bridge” that appeared in all the Municipalities between 1948 and 1952 created new jobs, and the new wages fuelled the consumer market, and facilitated the transportation of commodities. Construction sites appeared everywhere (they were “Learning Worksites”, “School for Construction Workers”); experimentation focused on reinforced-concrete bridges, with more or less audacious structural solutions, that could be produced by local firms employing unskilled workers. In 1951, Italy’s largest reinforced-concrete arch bridge was built (102 m span) over the Calignaia river, south of Livorno. In only three years, the laborious advances of the Sappers was just a memory. Now, on the decks of the new large arches, the engines of FIAT cars would be heard as they journeyed towards the economic boom