PSI - Issue 84

D. Di Fiore et al. / Procedia Structural Integrity 84 (2026) 159–166

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gives a more realistic economic output, which can make the most expensive solution advantageous if the time frame is long enough.

Fig. 8. Discounted OpEx when treatments are not repeated (left side) and vice versa (right side)

From a performance point of view (see Fig. 9), it is clear that the “To do nothing” approach yields poor results and requires continuous monitoring and inspection of the asset to ensure safety and service continuity whilst the repetition of treatments leads to the organisation meeting its objectives in terms of structural sustainability.

Fig. 9. Structural performance when treatments are not repeated (left side) and vice versa (right side)

The tool is continuously being enhanced to address engineers’ decision-making needs and to provide increasingly robust life-cycle assessment outcomes. Ongoing developments focus on refining deterioration models for homogeneous groups of tunnels in terms of age, materials, and construction techniques, leveraging the extensive visual inspection data available within the Organization. This evolution will allow a progressive transition from conservative assumptions to data-driven predictions, improving the reliability of long-term cost, performance, and sustainability assessments. Ultimately, TR&NDS is intended to support a proactive, risk-informed and sustainable tunnel management strategy, enabling infrastructure owners to optimise investments while ensuring safety, service continuity, and environmental responsibility over the entire asset lifecycle. References Alessio C., Di Fiore D., Baccolini L., Chiaia B., & Conte M. (2024) – Development of a tunnel asset management tool from a risk-based approach. In Yan et al. (eds.), Tunnelling for a Better Life; Proceedings of the ITA-AITES World Tunnel Congress 2024 (WTC 2024), Shenzhen, 19-25 April 2024 . CRC Press: London, pp. 3557-3566