PSI - Issue 78

Antonio Cefalì et al. / Procedia Structural Integrity 78 (2026) 1350–1357

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1. Introduction Growing global attention on infrastructure safety, driven by catastrophic events, highlights the crucial role of geotechnical monitoring in preventing and managing risks, thereby enhancing the resilience of national transportation networks. This is particularly vital for road infrastructure in seismically active and hydrogeologically vulnerable regions. This paper critically reviews current geotechnical monitoring technologies and methodologies, covering traditional and innovative instruments, integrated systems, and automated data acquisition. It also explores integrating satellite data with predictive models for assessing slope and structural stability, key components of road networks in geologically active areas. The analysis emphasizes how continuous monitoring, supported by advanced geotechnical analyses and early warning systems, significantly reduces geohazard risks, streamlines emergency management, and prioritizes interventions. The insights aim to contribute to operational guidelines for effective monitoring systems, supporting global resilience and sustainability policies for transportation infrastructure. Historical events unequivocally demonstrate the urgent need for robust geotechnical monitoring. Catastrophes, often due to inadequate monitoring and understanding of ground-structure interaction, have caused significant loss of life and economic disruption. Examples include the 2009 A2 Mediterranea highway landslide in Italy and numerous global incidents involving unstable slopes, embankments, bridge foundations, or tunnel sections (Angeli et al., 2000; Bagwari et al., 2022; Brunetti et al., 2025; Thirugnanam et al., 2022). While the 2018 Polcevera Viaduct collapse was structural, it underscored the intrinsic link to geotechnical performance and the need for continuous monitoring. These events collectively stress the necessity of understanding and continuously controlling the intricate interactions between infrastructure and its geological environment. Globally, the importance of comprehensive monitoring frameworks for infrastructure safety has steadily gained recognition. Early legislation, such as Law no. 64 of 1974 (Italy, 1974), focused on seismic design. However, a more systematic approach to long-term, continuous monitoring has progressively gained traction (Italy, 2014, 1988, 1984), shifting towards mandating control plans and real-time data for critical infrastructure. International and national initiatives are increasingly developing operational guidelines and best practices to standardize monitoring system design, execution, management, and maintenance, and to improve information collection and dissemination across all risk management phases. This global effort underscores a universal commitment to leveraging advanced geotechnical monitoring for safer, more resilient, and sustainable transportation infrastructures worldwide. 2. Geotechnical monitoring of bridges and tunnels Geotechnical monitoring of bridges and tunnels is crucial for ensuring their safety and functionality, especially in seismically active regions. These structures are often subjected to complex interactions with the surrounding ground, making continuous mon itoring indispensable. The rules for bridges and tunnels, such as the italian “Guidelines for the classification and risk management, safety assessment, and monitoring of existing bridges” (Italy, 2022a) and italian “Guidelines for the classification and risk management, safety assessment, and monitoring of existing tunnels” (Italy, 2022b), emphasize a multi-level approach to inspections and monitoring. Initial visual inspections are typically followed by in-depth examinations and structural stability checks for critical structures. All collected documentation, including drawings, reports, and photographic evidence, must be systematically organized in a dedicated file for each structure. For bridges, the guidelines advocate for continuous monitoring of foundation movements, piers, abutments, and affected ground, integrated within a main monitoring system (Vardanega et al., 2016). Various types of instrumentation and sensors are available for integration into Structural Health Monitoring (SHM) systems to achieve this. Hydraulic monitoring is also critical for bridges exposed to hydraulic risks, necessitating the installation of sensors to measure water velocity, flow rate, and water level, potentially with automatic alarm systems linked to meteorological stations (Crotti et al., 2016). Furthermore, specific detection systems are required to verify the efficiency of confinement works and flow control in areas near the bridge. The monitoring of natural and artificial slopes affecting bridges is another vital aspect. Landslide events are frequently linked to seismic actions or specific rainfall intensities and durations (Kumar M. and Ramesh, 2022). However, triggers associated with the progressive reduction of soil and rock resistance are challenging to detect and quantify (Kliche, 2019; Nocilla and Urciuoli, 1997; Wyllie and Mah, 2017). Therefore, landslide monitoring projects