PSI - Issue 44

Ubaldo Saracco et al. / Procedia Structural Integrity 44 (2023) 721–728 Ubaldo Saracco et al./ Structural Integrity Procedia 00 (2022) 000–000

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structural robustness. The study herein presented aims to define and verify a working methodology to obtain the maximum degree of knowledge of a bridge for its geometrical-mechanical characterization. The analyses set out below are necessary for a correct monitoring of the bridge structure health state. The approach herein presented aims at raising awareness of the general opinion regarding a careful control of the bridge structure and its future transformations. The hope is that a more conscious approach can lead to a correct planning of maintenance interventions which, often to the credit of the news, represent the main causes of risk for the structures. In fact, among the different types of structures, many examples of collapses can be found in the history of bridges (Wikipedia, 2022). Still, decay does not necessarily lead to collapse, particularly if it is well identified and repaired with efficient interventions (Yamaguchi et al. 2010) (Fig. 1).

Fig. 1. Kisogawa Ohohashi Bridge in Japan.

2. Case study The case study structure is the Pastorella bridge located in Lauria, a little municipality in the district of Potenza within the Basilicata region of Italy (Fig. 2). The bridge structure (Coord. 40 ° 02'57.8 "N 15 ° 50'39.1" E) was built in 1929 and is made of two steel trusses with a span of 73 m. Decommissioned in 1987, it presents an advanced decay state due to corrosion. In 1985 it was covered by the architecture and cultural heritage protection bounds delivered by the Superintendence of Archaeology, Fine Arts and Landscape of Basilicata. In 2017 it was refurbished by the municipality of Nemoli with the new use of greenway and it is currently open to the public by the municipality of Lauria.

Fig. 2. Picture of the Pastorella bridge in Lauria (district of Potenza) (ph. U. Saracco).

The research carried out saw the execution of on-site investigations following web research. In fact, unfortunately, due to the sanitary situation in Italy due to the CoVid-19 epidemic, the consultation of historical sources derived from archives and offices was not performed. However, the acquired historical news allowed to know that the Pastorella bridge is part of a larger railway route that connected Lagonegro with Spezzano Albanese, which are two termini of the national rail transport of Italian Railways. This connection path is a narrow-gauge line (wheelbase of 950 mm), while from Lagonegro to the north and from Spezzano Albanese to the south, the path is an ordinary gauge line (wheelbase of 1435 mm). The reason of this choice came from the fact that the connecting stretch of the two railway stations had to cross a particularly rugged territory from an orographic point of view. Despite the valuable engineering solutions, the line suffered a series of problems, such as extremely long travel time, several structure problems along the line and, finally, World War II bombing. Given these problems, in January 1979, the line was officially abolished and, in 1984, the tracks were removed from the headquarters, whereas the rest of the structures were left in their