DInSAR–SBAS satellite monitoring of infrastructures: how temperature affects the “Ponte della Musica” case study

Abstract

Continuous monitoring of the structural health of strategic structures and transport infrastructures plays a crucial role in providing an effective assessment of the safety conditions and in timely planning of the ordinary and extraordinary maintenance programme. Deformation monitoring and dynamic characteristic identification are some commonly used strategies for this purpose. One of the main challenges of recent years in the field of structural health monitoring is the use of data deriving from satellite interferometry, capable of providing information on structural deformations at a local and territorial scale. Despite the solidity and dependability of satellite-based methods for assessing ground deformation over time, when it comes to structural surveillance, there are certain circumstances under which satellites are incapable of accurately assessing displacements. This is particularly true for structures that are sensitive to temperature variations. The paper uses the “Ponte della Musica–Armando Trovajoli” in Rome as a case study to explore these aspects in more depth. This bridge has a steel arch structure with a prestressed concrete deck below it. It represents an example in which satellite differential interferometry does not allow obtaining useful information on displacement, at least for the most deformable portion of the deck, and therefore also on any pathological movements. This work proposes a 3D digital twin of the bridge, appropriately calibrated through experimental measurements of the environmental vibrations performed on the bridge. This will allow to evaluate the role played by thermal deformations related to air temperature variations and thus better understand the connection between physiological deformations and satellite limits.

Identifying Damage in Structures: Definition of Thresholds to Minimize False Alarms in SHM Systems

“…Starting from the understanding that the likelihood of incorrectly assessing the presence of damage is less in the case of critical events of considerable intensity, such as strong earthquakes, from the perspective of developing automatic systems for damage assessment, it is also crucial to reduce the uncertainties related to the variation in vibration frequencies related to phenomena not necessarily indicative of damage. Figure 1 shows an example of minor frequency variations observed on a real accelerometer acquisition performed on an operational bridge under normal conditions [34].…”

“…Starting from the understanding that the likelihood of incorrectly assessing the presence of damage is less in the case of critical events of considerable intensity, such as strong earthquakes, from the perspective of developing automatic systems for damage assessment, it is also crucial to reduce the uncertainties related to the variation in vibration frequencies related to phenomena not necessarily indicative of damage. Figure 1 shows an example of minor frequency variations observed on a real accelerometer acquisition performed on an operational bridge under normal conditions [34]. In this regard, the small frequency variations can be linked to many phenomena such as, for example, the combination of input and transient response of the system, the opening and closing of cracks and micro-cracks, and the nonlinearities due to interaction between the various structural and non-structural components.…”

An Innovative Sensor Integrated with GNSS and Accelerometer for Bridge Health Monitoring

“…A data-driven model for extensive wind turbine blade monitoring was proposed using a single accelerometer and actuator [16]. Ponzo achieved eigenfrequencies and the equivalent viscous damping factor using an accelerometer [17] and demonstrated that force-balanced accelerometers detected the fundamental frequency of the investigated bridge, which was less than 1 Hz [18]. However, accelerometers are likely to be affected by environmental factors, such as temperature and humidity, and are sensitive to the installation location and orientation [19,20].…”

Mass and Stiffness Correlation Using a Transformation Matrix

“…A good correlation between a numerical and an experimental model demands a good correlation in mass and stiffness, as well as in the internal (joints) and external (supports) boundary conditions [11]. The significance of correlation techniques is highlighted by their diverse applications in various fields, such as in civil (bridges, dams, towers [12,13], buildings, etc.…”