PSI - Issue 64

Amedeo Caprino et al. / Procedia Structural Integrity 64 (2024) 2149–2156 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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2.4. Structural verification Structural verification was conducted according to NTC08 standard ( NTC2008 Norme Tecniche per le Costruzioni , 2008). First, through the implementation of a numerical model of the bridge, the stresses acting on the main girders at the main sections (lateral span, central support, and central span) were calculated assuming two load configurations: two-lane (2L) and three-lane (3L). Next, the resistances of the load-bearing elements were calculated. Three different scenarios were assumed to simulate the deteriorating conditions in which the structure is located. The first involves considering undamaged beams, using the design mechanical properties of the materials. Scenarios 2 and 3 involve considering damage to the elements and the consequent reduction in resistant section, reducing the mechanical properties by 20% and 40%, respectively. From the results presented in Fig.3 as ratio load/resistance, it is possible to deduce that generally the 2C solution proves to be safer. This difference turns out to be unremarkable for the internal beams, where the two load combinations do not change much in the two cases, while it is more evident for the external beams; this solution, in fact, bears less load on the edge beams which are also the most damaged. In any case, considering the damaged condition of the beams, neither 2L nor 3L configuration satisfy the safety requirements, hence reparation interventions are unequivocally required.

Fig. 3. Results of the conducted structural verification.

3. Structural Monitoring system Considering the relevance of the bridge to connect the city center of Verona across the Adige river, but also the serious damage condition of the bridge, it was decided to keep the bridge in service, although with severe traffic limitations. Therefore, it was deemed necessary to install a monitoring system on the bridge, to check in real time its safety conditions, and support the decisions to be taken on the future interventions. The monitoring system implemented for the control of bridge’s structural parameters is aimed at the acquisition of the vibrational characteristics of the structure, recorded through acceleration transducers, and at the evaluation of displacements under operating load, obtained through displacement transducers (Fig. 4.). These readings are related to environmental parameters (temperature and relative humidity). The installation of the monitoring system took place