PSI - Issue 84

M. Viviani et al. / Procedia Structural Integrity 84 (2026) 931–936

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The first assessment concerned the stress state of the bridge structure following the failure of the restraint system. Analyses were carried out on various systems without fixed ends. The results, in terms of stresses, showed that the elastic limits were not exceeded, for both ordinary and high-strength steel, as well as for the concrete. A detailed visual inspection, carried out after the repair, confirmed the numerical analyses, ruling out any damage, including that caused by possible dynamic effects during the failure of the restraint system. The cable passages in the viaduct abutment were originally protected with mineral wax, specifically ozokerite, which can be liquid at relatively low temperatures, between 60 and 100 °C. Thanks to this knowledge, the repair design was prepared. 3. Viaduct repair In the absence of constraint for the abutment, the viaduct could not be considered safe and was therefore inaccessible to workers and vehicles. The first phase involved strengthening the structure by replacing the cables running through the abutment and reconnecting them to the upper section of the existing cables, which showed no particular signs of corrosion. To this end, a steel coupler was designed, which made it possible to tension the cables and restore the viaduct’s safety (Fig. 5a). Once safety conditions were restored and the original construction method identified, the repair proceeded in the usual manner, replacing the cables one by one and tensioning them to the specified load to ensure stability under any load condition (Fig. 5b). a b

Fig. 5 – Provisional join (a) and final tension (b)

Fixing work ended with the load testing, before reopening. At the end of the work, a real-time monitoring of the structure has been planned to ensure its function. Nowadays monitoring is still in process.