PSI - Issue 64

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

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In Table 4 and Table 5, the mean and the standard deviation parameters are shown for each local mechanism activation and both flexural and shear failure modes. In addition, the min curve is evaluated depending on the first local mechanism activation for each structural model. The masonry panel exhibits a high vulnerability to the flexural mechanism in both sets of analyses. Comparing the fragility curves, the structural vulnerability is reduced increasing the compression axial force of the masonry due to the direct relation to the flexural and shear capacities of the structural elements.

Table 2. Mean and standard deviation of fragility log-normal curves for structural models with 1 storey. Parameter M V s V t Min μ [mm] -1.953 -0.695 -0.834 -1.995 σ [mm] 0.819 0.794 0.859 0.763 Table 3. Mean and standard deviation of fragility log-normal curves for structural models with more than 1 storey. Parameter M V s V t Min μ [mm] 0.191 0.551 0.785 -0.109 σ [mm] 0.677 0.947 0.838 0.679

5. Conclusions This work aims to investigate the sensitivity of structural failure due to vertical settlements of masonry buildings in order to assess their monitorability with satellite systems. In particular, the main goal is to compare the order of magnitude of the settlements recorded by SAR technology with the displacements that activate in-plane local mechanisms in masonry structures, investigated in terms of flexural, sliding shear and diagonal shear failure modes. A large-scale approach has been considered to perform structural analyses on several structural models. Global mechanisms have been neglected in this work due to the low knowledge level achievable on masonry structure. A sample of over 30,000 buildings has been generated with several Monte Carlo analyses. The structural models have been designed according to empirical and analytical equations available in literature based on common practices at the age of construction and to historical Italian codes. Linear static analyses have been performed considering two set of analyses; the first one is related to structural model with 1 storey while the second is related to structural model with more than 1 storey. The results of the structural analyses are shown by means of histograms and fragility curves using the Maximum Likelihood Estimation method. The results show a high vulnerability of the masonry piers where the settlement is associated to flexural failure mode due to the significant induced tensile axial loads. Increasing the number of storeys of the buildings and, consequently, the axial load in compression in masonry piers, the vulnerability to flexural failure mode is reduced with a consequent increase of the vulnerability of the masonry spandrel. The results shows that few millimeters are sufficient to activate in-plane mechanisms; SAR technology allows to detect this order of magnitude of displacements but it is also important to focalize the attention on the post processing and the interpretation of satellite data to retrieve consistent information on the settlements of the structures. Future work could be based on the comparison between the results of this numerical work with a case study. One of the limits of this study is represented by the simplified structural models adopted in the analyses that do not allow to appreciate the tridimensional effects of the structural behavior of the buildings. In addition, out-of-plane mechanisms are not considered in this study.