PSI - Issue 84

E. Renzi et al. / Procedia Structural Integrity 84 (2026) 1361–1368 E. Renzi et al. / Structural Integrity Procedia 00 (2026) 000–000

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The new Operating Instructions are editorially placed within the previous ones of 2002, so as to ensure the concurrent availability of the Bridge Guidelines, the 2022 Operating Instructions—which remain unchanged—and the new additional indications. The new Operating Instructions can be grouped into the following types: 1. Integration of the tables in the Operating Instructions annexes : An integrated and more detailed set of information is made available compared to what is provided by the Bridge Guidelines and the current Operating Instructions. The aim is to provide, when deemed necessary and without prejudice to activities already carried out, a deeper level of detail in the reference information for the development of subsequent levels. To this end, a series of supplementary annexes are provided as a useful aid for practitioners. For example, with reference to the Level 1 Forms, new forms specific to certain structural elements are attached, such as Gerber elements, plinth blocks, stay cables and hangers. 2. References to established practices and circumstances : Information is made available that reflects the body of established practices and the expertise of practitioners and specialists. 3. Clarifications : Possible assessment criteria (within the scope of what is set out by the Bridge Guidelines) are clarified in order to achieve a higher level of uniformity in assessments for which no indications had previously been provided. 4. References in the absence of specific regulatory provisions : Indications are provided that might reflect in the future in new releases of the Guidelines and could be presently voluntarily adopted by individual operators. The main significant innovations introduced by the new Operational Instructions concern: • Integration of census, defect, and inspection forms. • Clarifications and specifics about the criteria for evaluating the severity of structural/foundational and seismic defectiveness. • Further guidance and improvement of procedures for inspection, classification and assessment of hydraulic and landslide risks where the IG and OI of 2022 provided only general principles. • Guidance on the frequency of ordinary inspections, based on both the Overall Warning Class and the Warning Classes related to individual risk sources. • Indications about instrumental monitoring systems. In the following paragraphs, some of the most interesting Operating Instructions are discussed, with reference to the specific aspects relating to structural–foundation and seismic risk, hydraulic risk, and landslide risk. 1.1. Integration and harmonization of census, inspection and defect forms annexed to IG The update of the Operational Instructions includes a series of annexes, including some concerning registry forms, inspection forms, and surveys of structural and seismic defectiveness. For example, the Level 0 inventory form and the descriptive inspection form, contained respectively in Annex A and Annex B of the 2022 Guidelines (MIMS, 2022), have been revised and supplemented to make compilation more effective, systematic, and clear, thereby facilitating the work of managers, also in view of the digitization of data and processes. The integrations and reorganizations have not introduced changes to the parameters involved in the Attention Class calculation flow and maintain full interoperability with the inventory and inspection work already carried out. They concern the following aspects: • Harmonization and explanation of the nomenclature and definitions of the parameters present in the Level 0 form, in the text of the Guidelines, and in the Level 1 forms. • Integration of parameters with those provided by the AINOP system , to enable interoperability of digitized data. • Rationalization of the data to be collected in the census form , through the separation into a section of mandatory data—for classification and AINOP integration purposes—and a section of optional “additional data” in which to allocate knowledge data on the existing infrastructure assets, based on a nationally shared homogeneous data structure