PSI - Issue 78

Lorenzo Ciccarelli et al. / Procedia Structural Integrity 78 (2026) 1428–1435

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Fig. 6. Nonlinear dynamic analyses: (a) accelerogram with failure times; (b) normalised Arias intensity with failure times.

Furthermore, focusing on the normalised Arias Intensity (Figure 6b) as indicator of the energy content of the ground motion input, it can be observed that the earlier failure corresponds to a significantly lower amount of energy required to induce structural collapse: approximately 28% less when comparing the C1 and NC scenarios and around 43% less when comparing the C2 and NC scenarios.

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Fig. 7. (a) moment-rotation diagram Ry-My; (b) moment-rotation diagram Rz-Mz.

Finally, a comparison of the Moment – Rotation capacities in the y (Figure 7a) and z (Figure 7b) direction showed that increasing degradation led to a reduction in the structure’s maximum capacity and overall dissipated energy. A significant decrease in ductility was also observed, particularly in the z direction, along with a more brittle behaviour under negative moment in z for C2. 5. Conclusions This paper presented the application of the Italian guidelines for the multi-risk assessment of existing bridges and viaducts to a real case study, i.e., the bridge in Calabria region, south of Italy. The analysed bridge satisfied the static verification r equirements for the “operational bridge” condition but failed to meet the seismic performance criteria. To gain deeper insight into the structural behaviour under dynamic loading, a nonlinear time history analysis was carried out, allowing for the inclusion of material nonlinearity effects. Although more computationally demanding, this analysis provided a mo re realistic representation of the bridge’s seismic response. A key focus of the study was the impact of material degradation, specifically reinforcement bar corrosion, on the structural capacity. The inclusion of corrosions effects in the model, through two degraded scenarios, revealed that even low levels of corrosion lead to a significant reduction in both load-bearing capacity and ductility. The comparison between degraded and non-degraded models clearly highlighted the importance of accounting for such phenomena in