PSI - Issue 84

Michele D’Amato et al. / Procedia Structural Integrity 84 (2026) 1175–1182

1176

Keywords: Post-tensioned concrete bridges; Prestressed concrete bridges; Material strength; SAFOTEB database; Statistical analysis; Goodness of-fit tests.

1. Introduction Growing evidence of deterioration and sudden failures in transportation infrastructure (Bazzucchi et al., 2018; D’Amato et al., 2024; Lo Monaco et al., 2024; Ranaldo et al., 2024a; Contardi et al., 2025; Salvatore et al., 2026) have emphasized the need, both within the scientific community and among infrastructure managers, to develop reliable tools for assessing the safety and remaining service life of existing bridges (Du Beton, fib, 2016; Tatangelo et al., 2024). In this context, accurate knowledge of the mechanical properties of construction materials plays a central role, as these properties often exhibit significant variability and uncertainty, compounded by the scarcity or incompleteness of original design documentation. The need for systematic and updated datasets also aligns with broader research initiatives aimed at adopting verification formats based on probabilistic and Bayesian approaches, capable of integrating prior information with experimental test results (Micozzi et al., 2023; Poeta et al., 2025; Ranaldo et al., 2024b). Within this framework lies the research project titled “A reviewed SAfety FOrmat for structural reliability assessment of post-TEnsioned concrete Bridges” (briefly, the SAFOTEB project), funded by FABRE consortium (a Research Consortium for the Evaluation and Monitoring of Bridges, Viaducts, and Other Structures (https://www.consorziofabre.it/)). The project aims to assess the residual life of existing post-tensioned concrete bridges, including their typical degradation mechanisms, and based on a partial factors format. Involving multiple Italian universities and engineering partners, the research included applications to representative case studies (Rossi et al., 2024; Meoni et al., 2024). This paper aims to address the lack of systematic data on materials used in Italian prestressed concrete bridges by developing a structured database of reinforcing steel, concrete and prestressing steel strengths. The SAFOTEB database was constructed by anonymously analyzing a sample of approximately 170 bridges located in various Italian regions and built between 1960 and 2000, drawing from design nominal values, acceptance certificates, and in situ tests. Following a description of the data collection process and the database organization, the study presents a statistical analysis of the mechanical properties collected and verifies, through goodness-of-fit tests, the hypothesis of normality for reinforcing steel and prestressing steel and log-normality for concrete. The results obtained constitute a significant resource for researchers and practitioners, providing a quantitative reference useful for preliminary assessments and for Bayesian frameworks aimed at reducing uncertainties through the integration of prior knowledge. 2. SAFOTEB database A comprehensive database was developed to collect the material strengths used in Reinforced Concrete (RC) girder bridges having Prestressed Concrete Beams (PCBs). The study analyzes a sample of 168 bridges built in Italy between 1960 and 2000, encompassing both Pre-Tensioned Concrete Beams (Pre-TCBs) and Post-Tensioned Concrete Beams (Post-TCBs). The geographical distribution and some bridge typology examined are presented in Fig. 1a and Fig. 1b, respectively. The Fig. 2a shows that the sample set primarily consists of bridges designed between 1961 and 1980 (68% - 114 bridges), plausibly built in accordance with Circular of the Ministry of Public Works of 14 February 1962, no. 384 (C.M.P.W., 1962). Moreover, a not negligible percentage of bridges (15% - 25 bridges) lack a specific design year, indicated as not available (NA). With reference to the beams construction materials adopted, a summary analysis of the collected bridges sample is presented in Fig. 2b. In particular, the sample is composed by 93% (156 bridges) of PCBs, of which 78% (131 bridges) were realized with Post-TCBs and the remaining 15% (25 bridges) with Pre-TCBs. Meanwhile, only 4% (7 bridges) were realized with RC beams, and 2% (4 bridges) with beams resulting from mixed materials (such as steel and RC associated with PC). Finally, the percentage of bridges with an unspecified construction type (NA) is negligible.