PSI - Issue 84

S. Lorefice et al. / Procedia Structural Integrity 84 (2026) 669 – 676

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For the application of reinforced plaster on the extrados of arches and spandrels, the original fill (unit weight ≈ 24 kN/m³) must be completely removed and replaced with a lightweight stabilized mix (unit weight ≈ 18 kN/m³) to reduce stress levels and improve overall structural stability.

Fig.9. Model of the welded wire mesh

9 Results of Post-Operam Analyses – Existing Bridges Pushover analyses along the longitudinal and transverse directions were repeated under post-operam conditions, accounting for the strengthening interventions and the presence of the new steel structure. The interpretation of results follows the same considerations as for the ante-operam analyses.

a)

b)

Fig.10. Example of output data for (a) longitudinal e (b) transversal pushover – six-span bridge, post-operam

c)

d)

Fig.11. Example of output data for (c) longitudinal e (d) transversal pushover – three-span bridge, post-operam

10 Conclusions The seismic safety of the masonry approach structures was assessed through the calculation of the Risk Index (IR) , defined as the ratio of the seismic capacity of the structure to the seismic demand in terms of peak ground acceleration: ( ) = / Higher IR values indicate greater seismic safety