PSI - Issue 78

Adriano Andrés Del Fiol et al. / Procedia Structural Integrity 78 (2026) 1713–1720

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Fig. 4. a) Comparative analysis of experimental (red) and analytical modelling methodologies (blue) for cyclic tests on a bare frame. b) the tensile damage (DAMAGET) distribution for the bare frame model at the ultimate state is presented herewith. 4.2. RC Frame with Masonry infill model The model with the masonry infill panel effectively simulates the stiffening effect and increased lateral load resistance introduced by the infill. In comparison with the experimental curves, the first cycles, perfectly reproduce the experimental curve, getting perfectly the unloading stiffness (Fig. 5a). Nevertheless, in the cycles for higher drifts, the numerical model was not able to faithfully reproduce the damaged response of the panel in the reloading phase. Hence, the numerical model showed the trend of overestimating strength and of reducing degradation in subsequent loading stages. This phenomenon may be attributed to the full tie constraint assumption present at the frame-infill interface. Overall, the model successfully captures the qualitative trend and the influence of the infill on frame behaviour. The damage mechanism of the infilled frame is illustrated in Fig. 5b. The presence of the masonry infill panel caused a fundamental alteration to the structural response. The damage plot provided clear evidence of the development of a diagonal crack, usually observed in experimentally tested masonry-infilled frames. This is shown by a wide band of high tensile damage that extends from the top-loaded corner to the opposite column, typical for panels with a width-high ratio bigger than one, and a diagonal one, due to a compressive strut mechanism. The result obtained is anyway consistent with the expected infill response, validating the model ability to capture the essential infill-frame interaction. It is evident that minor damage concentrations manifest in the surrounding frame at the points of contact with the compression strut.

Fig. 5.a) Comparative analysis of experimental (red) and analytical modelling methodologies (blue) for cyclic tests on a RC frame with masonry infill. b) The tensile damage (DAMAGET) distribution for the masonry infilled frame model at the ultimate state is presented herewith.

4.3. Comparison of the models This comparison underscores the pivotal function of masonry infill in enhancing the stiffness and lateral load capacity of the RC frame (Fig. 6). However, it also demonstrates diminished ductility and constrained deformation