PSI - Issue 84

M. Cademartori et al. / Procedia Structural Integrity 84 (2026) 384–391

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Infrastructure managers such as ANAS, RFI, and ASPI have developed their own technical documents to fill operational gaps, especially on testing and modelling. Internationally, countries like the UK, Switzerland, and the US already provide mature and detailed standards for bridge assessment, including full load-rating procedures. At the European level, the transition to the second-generation Eurocodes is underway: for the first time, a dedicated Eurocode (EN 1990-2) for the assessment of existing structures is expected in 2026, complementing current documents such as CEN/TS 17440 and future updates of Eurocode 8. 3. Discussion about the portfolio of bridges under consideration In order to contextualize the recent experiences on the assessment of existing bridge and highlight what designers typically interact with, this paragraph reports the data relative to the bridge stock under study as: period of construction, material and construction technologies, structural configurations, and other relevant parameters of the works of art examined. It should be noted that the bridges, viaducts and flyovers discussed below fall under the responsibility of various Italian managing authorities and are in different regions of Italy with different characteristics and different condition state. Another recent work dedicated to the analysis of an Italian bridge stock but mainly focusing on the material strength is reported in D’Amato et al (2025). 3.1. Presentation of the properties of the bridge stock In the analyzed bridgeportfolio,totaling 102structures, almost 45% were built between 1962 and 1980, with an average age of about 50 years. More than 25% were built between 1981 and 2000, with an average age of approximately 35 years. Around 20% were built between 1952 and 1961, with an average age ofnearly 70years. More than 5% were built before 1952 and finally the remaining ones 5% after 2001 [Fig. 1]. The most concerning finding is not the one related to the age of the analyzed structures. One might reasonably assume that the older a structure is, the higher the risk it presents. It is indeed normal for these structures to have shown various types of problems, since they have exceeded the designed service life and are now subjected to loads different from those originally considered in the design phase. However, the analysis of the bridge stock highlights that relatively new bridges present some structural degradation requiring detailed assessment. In this portfolio, the most common structural configuration is the simply supported beam with more than 60%. Both the continuous beam scheme and Gerber girder configuration represent 9%, while the arch structural scheme accounts for 12%. Finally, the massive slabs and the box girders account for 5 and 6% respectively [Fig. 2].

Fig. 1. Bridge stock grouped by period of construction Fig. 2. Bridge stock grouped by structural configuration As far as the number of spans is concerned, the most common structures are single-span overpasses or underpasses, which account for more than 30%. It should be noted, however, that unlike the European context, in Italy a structure is classified as a bridge, viaduct or fly-over only if it is at least 6 m long. Slightly less than 30% is the share of structures with 2 to 5 spans. The trend shown inFig.3indicates that as the number of spans increases, the percentage of ones assessed decreases.