The Development of Compressed-air Foundations in Italy: the Tiber River Embankments (1876-1900

The paper addresses the use of compressed-air caisson foundations technology for the construction of both the Tiber walls in Rome (1876-1900) and the river bridges (1940s). Since the first construction sites of the river walls (1876), the traditional use of the cofferdam foundation method was deemed unsuitable, in terms of stability of the structure and construction times and costs. In 1878, the use of compressed-air foundations, with metallic caissons, was first proposed. In 1882, the adoption of this method, still pioneering in Italy, was declared mandatory for all the river’s walls extension in the centre of the city. The same method was adopted for the construction of the deep foundations of the rivers bridges, built in the same years up to the 1940s. Thus, the construction history of both the river walls and the river bridges, disclosed the pioneering experimentation on the pneumatic caisson method carried out, between 1882 and 1900, by the Italian firm “Impresa Industriale Italiana di Costruzioni Metalliche” and by the Swiss firm “C. Zschokke & P. Terrier”, and the evolution of the same method, adopted by Italian firms up to the 1940s.