PSI - Issue 84

Beatrice Baldan et al. / Procedia Structural Integrity 84 (2026) 569–574

572

constitutive and bond parameters required by nonlinear finite element analyses, which are often difficult to identify for existing bridges. In summary, the elastic C scheme represents the initial, non-redistributed structural response , providing the reference state from which more advanced analyses with plastic redistribution can be developed.

Figure 2 Strut-and-tie model

4. Results The graph highlights the comparison between the analytically predicted values and the corresponding experimental results through the ratio Δ = an / exp plotted for each test. Overall, the analytical model exhibits a recognizable trend rather than a purely random scatter. The ratio Δ generally assumes values below unity, mostly falling in an intermediate range that indicates a tendency of the elastic analytical formulation to provide lower strength estimates than those observed experimentally. The dispersion remains appreciable, but not erratic, suggesting that the model retains a degree of internal consistency across the test series. This behavior implies that, within the elastic framework, the analytical approach captures the principal mechanical features governing the response, while the simplifying assumptions inherent to linear-elastic idealization—such as cracking-induced stiffness degradation, ideal boundary conditions, and the neglect of secondary redistribution mechanisms—may contribute to reduced predictions of capacity. The variability observed in the ratio values points to a sensitivity of the analytical outcome to specimen-specific characteristics, which are only partially reflected in the simplified formulation. Consequently, the figure indicates that the elastic solution provides a coherent but approximate representation of the structural response, with a generally conservative bias.