PSI - Issue 84

Michela Briganti Botta et al. / Procedia Structural Integrity 84 (2026) 344–351

349

The intervention is required due to severe deterioration of the waterproofing system, which has caused significant infiltration inside the structure, leading to progressive decay and, without corrective action, potential structural damage. The photos clearly show both the infiltration phenomena and emergency stabilization works already carried out on one of the piers. The viaduct also shows expulsion of stone material, a sign of axial stresses reaching high levels along certain stone edges. The structure has a width of 9.30 m, originally adequate for double-track operation, but currently insufficient to allow safe inspection/maintenance activities along the tracks. Moreover, the massive seaward-side parapet reduces the usable platform to just 8.55 m (current standards exceed 12 m). Consequently, RFI needs to install steel walkways to ensure inspection and maintenance activities with the required safety distances. • Origin and Historical Background The viaduct is a historically significant structure dating from the mid-19th century. During World War I, it was heavily shelled in several areas but did not collapse. Attempts to retrieve the original design documents were unsuccessful, but several photographs from after the wartime bombardments were found. These images clearly show the severe damage suffered, especially to the tympanum masonry and the parapet above it. Some parapet sections destroyed by shelling were rebuilt in concrete (including the cubic decorative elements beneath the stone projection supporting the parapet). On the mountain side, however, the original parapet was completely removed and replaced with a metal railing. The bridge spans a ravine between the Moschevizza and Sablici hills—a strategically important military location— where Italian and Austrian troops fought fiercely, as evidenced by the remains of military fortifications still present today. Other clues from the photographs show that the viaduct also served as shelter for the Italian front line (positioned directly behind the piers during the advance toward the Sablici heights) and that a war cemetery once stood at the foot of the viaduct (now the site of the motorway toll station). The history of this area has therefore deeply shaped the landscape, which is now partially protected under the regional landscape plan of Friuli Venezia Giulia. Maps show that the viaduct lies exactly on the boundary of the landscape-restricted area and on the border between the municipalities of Monfalcone and Doberdò del Lago.

Fig. 6. Front line of the Italian army 1915-1918