PSI - Issue 84

P. Saletti et al. / Procedia Structural Integrity 84 (2026) 937–943

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Phase 2 – Foundation strengthening and reinforcement

Through detailed perforations, high pressure concrete mixtures have been injected (Fig.7). This allowed to saturate hollows inside boulder cliff and in the underground, creating a concrete “bulb” close to column’s basement (Fig.8).

Fig. 7 – Injecting of high pressure concrete mixture

Fig. 8 – Final stage of strengthening

Phase 3 – Monitoring and finishes During the major construction work, both crack gauges and optical sighting devices were installed to monitor the progression of the cracks. Subsequently, minor repairs were made to the masonry and the road edge to correct the loss of straightness. 5. Technical validation and safety evaluation On September 2025, once concluded urgent works, Lucca’s Province committed final technical reports to certify bridge’s stability. The structural evaluations made from NTC 2008, and DM 204/2022 laws confirmed that strengthening work restored necessary safety coefficients. Calculations demonstrated that damaged column and overstanding arc are now able to bear operating loads as expected.