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Most of prestressed concrete viaducts built between 1950s and 1980s feature simply supported decks connected by various joining mechanisms. Therefore, experimental experience and studies aimed to extend knowledge about this structural typology can give a great support and interest for the infrastructure network management. In common SHM (Structural Health Monitoring) practice, damage identification techniques relies on detecting changes in dynamic behaviour. However, these variations are not solely due to damage progression: studies report that significant changing can be also associated with the variability of environmental actions (especially thermal effects) and operational loading conditions. This paper focuses on assessing the impact of typical damages in simply supported prestressed viaducts on the main vibration mode frequencies. To this end, Ambient Vibrations Tests (AVTs) were performed between December 2022 and February 2023 on Biferno and Saraceni viaducts, both located on the A14 highway, under regular traffic conditions. Specifically, a sample of n.10 and n.4 spans, respectively, was selected, on which Operational Modal Analysis (OMA) tests were conducted under comparable environmental and operational loading conditions. The analysed spans share the same structural scheme (42 m prestressed beams), the same bearing devices (steel pin-roller bearings) and a comparable structural health condition. Damaged roller bearings, exposed/corroded reinforcing bars and concrete edge spalling are the main defects identified through periodic on-site inspections. Modal parameters extracted from the AVTs are presented and the influence of defects on them is analysed in detail. The obtained results are intended to support monitoring activities aim to detect the experimental modal parameters of this common structural typology. Furthermore, this experimental evidence can represent a guide tool to assess the variability in structural frequencies, particularly in the first vibration modes, when typical defects of a certain extent and rate occurs.

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Influence of Defects on Modal Parameters Extracted by AVTs Processed Through OMA: Application to Two Full-Scale Viaducts

  • 会议论文

  • 发表日期：

    2025年

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  • Christian Alfonsi,
  • Noemi Fiorini,
  • Michela Silla,
  • Francesco Talanas,
  • Roberto Acerbis

摘要

Most of prestressed concrete viaducts built between 1950s and 1980s feature simply supported decks connected by various joining mechanisms. Therefore, experimental experience and studies aimed to extend knowledge about this structural typology can give a great support and interest for the infrastructure network management. In common SHM (Structural Health Monitoring) practice, damage identification techniques relies on detecting changes in dynamic behaviour. However, these variations are not solely due to damage progression: studies report that significant changing can be also associated with the variability of environmental actions (especially thermal effects) and operational loading conditions. This paper focuses on assessing the impact of typical damages in simply supported prestressed viaducts on the main vibration mode frequencies. To this end, Ambient Vibrations Tests (AVTs) were performed between December 2022 and February 2023 on Biferno and Saraceni viaducts, both located on the A14 highway, under regular traffic conditions. Specifically, a sample of n.10 and n.4 spans, respectively, was selected, on which Operational Modal Analysis (OMA) tests were conducted under comparable environmental and operational loading conditions. The analysed spans share the same structural scheme (42 m prestressed beams), the same bearing devices (steel pin-roller bearings) and a comparable structural health condition. Damaged roller bearings, exposed/corroded reinforcing bars and concrete edge spalling are the main defects identified through periodic on-site inspections. Modal parameters extracted from the AVTs are presented and the influence of defects on them is analysed in detail. The obtained results are intended to support monitoring activities aim to detect the experimental modal parameters of this common structural typology. Furthermore, this experimental evidence can represent a guide tool to assess the variability in structural frequencies, particularly in the first vibration modes, when typical defects of a certain extent and rate occurs.