PSI - Issue 64

3

Stefano Belliazzi et al. / Procedia Structural Integrity 64 (2024) 612–620 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 1. Structural model.

The main local mechanisms analyzed are the classic mechanisms of flexural failure, sliding shear failure and diagonal shear failure as reported in the current Italian standards NTC18: • Flexural failure (Fig 2.a): exceeding the flexural strength of the panel leads to the formation of tensile cracks on a side and crushing at the other corner subjected to compression. • Sliding shear failure (Fig 2.b): a mechanism caused by exceeding the shear strength for sliding, characterized by the formation of horizontal cracks. This mechanism is favored by low values of the friction coefficient and low levels of wall compression. • Diagonal shear failure (Fig 2.c): a mechanism caused by exceeding the tensile strength and governed by the formation of diagonal cracks.

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(b)

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Fig. 2. In-plane local mechanism: flexural failure (a), sliding shear failure (b) and diagonal shear failure(c).

The activation of the in-plane mechanisms generally depends on the geometric characteristics of the analyzed elements and on the slenderness ratio h/L of the element, where h indicates the height and L the length of panels. For slender panels, where the h/L ratio > 1.5, the failure mechanism is usually due to flexural stresses, while in squat panels, where the h/L ratio is less than unity, the failure is induced by shear stresses corresponding to the internal failure of the panel due to the exceedance of normal tensile stresses or sliding phenomena; but there is also a significant dependency with the normal axial load. For each mechanism, the checks consist in evaluating the settlement value necessary to activate a local failure mechanism in a structural element through linear elastic analysis.