PSI - Issue 78

Giuseppina Uva et al. / Procedia Structural Integrity 78 (2026) 1048–1055

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peak and a post-peak behaviour derived from the provisions given by the Model Code (Fédération Internationale du Béton, 2010) about the tensile failure of concrete in terms of tensile strength - crack-opening width (w) relationship. Figure 2 shows the specific plots of the skeleton curves and damage laws under compression and tension for the four materials of the bridge. Two types of FE models have been developed in Abaqus environment (Dessault, 2011). The first one (“Solid Model” - SM), is a detailed three-dimensional FE model in which all structural elements are modelled with their actual geometry by solid elements. The second model (“Shell-Box Model” - SBM), is also a three-dimensional FE model but has a simplified geometry reproduced by shell elements, so to reduce the number of degrees of freedom of the problem. The Solid Model is taken as a benchmark for calibrating the inertial and modal parameters of the Simplified Shell-Box Model. Then, the validation of the Simplified Model is performed through static non-linear analyses.

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Figure 2. Compressive behaviour of the four materials: (a) post-elastic skeleton curves in compression; (b) inelastic strain – damage_c curves. Tensile behaviour of the masonry materials: (c) post-elastic skeleton curves in tension; (d) inelastic strain – damage_t curves.

The geometry of the Solid Model has been defined reproducing as much as possible the real configuration of the structural elements. The availability of experimental data in terms of vibration frequencies and modal shapes has allowed the calibration of some parameters of the numerical Solid Model, (in particular, those that were not