PSI - Issue 84

Roberto Acerbis et al. / Procedia Structural Integrity 84 (2026) 765–772

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Keywords: Structural monitoring systems, operational workflow, asset management

1. Introduction 1.1. Pre Assessment and Post Assessment Monitoring

Decree No. 93 of April 12, 2022, issued by the Italian Ministry of Infrastructure and Sustainable Mobility (MIMS), involved 1,246 bridge and viaduct spans and tunnel segments of the ASPI motorway network to be subjected to continuous and automatic monitoring. As a result, a network-level strategy was required to select the structures to be monitored and to define the specific objectives of structural monitoring. Building upon the assessments previously carried out by ASPI within the multi-level approach defined by the national Guidelines, two distinct groups of structures were identified: • Structures for which an accurate safety assessment was available (Post-Assessment), for which material investigations had been performed and numerical structural models had been developed. For these assets, monitoring data can be used to assess the structural condition and to define performance-based structural thresholds. • Structures for which accurate safety assessments were not available (Pre-Assessment), for which a simplified approach is adopted. In this case, monitoring data are used to perform statistical analyses of measured parameters and to define anomaly detection thresholds. For the first group of structures, a Model-Based monitoring approach is adopted, while for the second group a Data Driven approach is implemented ( Hu, 2024).

Nomenclature MIMS Ministry of Infrastructure and Sustainable Mobility Guidelines Existing Bridges; Ministry of Infrastructure, CSLP: Rome, Italy, 2020.

Guidelines on Risk Classification and Management, Safety Assessment and Monitoring of

1.2. Main Monitoring Objectives: Data Driven and Model Based approaches In both approaches, the primary objective is to assess the evolution of the structural response under operational conditions, with the aim of: • identifying potential damage mechanisms; • quantifying natural ageing processes of the structure. The Data-Driven (DD) monitoring approach focuses on the evaluation of variations in the actual behavior of the structure by quantifying its response over time. This includes assessing displacements, rotations, and deformations, their frequency of occurrence, possible seasonal periodicity, and whether these responses remain stable or exhibit evolving, potentially irreversible trends. This approach reduces uncertainties associated with limited structural knowledge and allows maintenance and rehabilitation interventions to be optimized based on objective data collected through a limited number of sensors installed at key locations of the bridge or viaduct. The Model-Based (MB) monitoring approach integrates and extends the analyses typical of the Data-Driven approach by directly comparing the measured structural response with that predicted by a numerical model of the structure, suitably updated through model updating techniques. This is enabled by a more extensive sensor network, providing in-depth knowledge of both static and dynamic structural behavior. The MB approach also allows calibration of the numerical model considering existing damage mechanisms and a comprehensive evaluation of the effects of external actions. This enables optimization of maintenance and rehabilitation interventions based on objective data, as well as verification of the structural response during exceptional events. To this end, appropriate