"Martino Anzi" Middle School, Bormio (SO)

The aspects analyzed to achieve this level of knowledge include:geometry (the geometric characteristics of the structural elements), structural details (amount and arrangement of reinforcement, including stirrup spacing and closure for reinforced concrete, connections for steel, connections between different structural elements, and the composition of non-structural collaborating elements), and materials (the mechanical properties of the materials).

The investigation campaign was carried out according to the following program:

• Analysis of the available structural documentation (e.g., testing reports);
• Visual inspection to identify existing cracking or ongoing degradation;
• Instrumental survey to verify as-built conditions and integrate/correct any discrepancies with the available documentation;
• Reinforcement survey using a magnetometer;
• Concrete core sampling and laboratory compression tests;
• Ultrasonic pulse velocity tests to assess concrete homogeneity;
• Sclerometric tests to evaluate concrete uniformity;
• Reinforcement bar sampling and laboratory tensile tests;
• Hardness tests for the characterization of metal carpentry elements;
• Flat-jack tests for determining the deformability of masonry structures and estimating their compressive strength;
• Core sampling of masonry;
• Videoendoscopic inspections within masonry and floors;
• M.A.S.W. tests near the building foundation to characterize the seismic properties of the soil, including direct evaluation of the Vs30 parameter;
• Minor, minimally invasive restoration of finishes at the points under investigation.

The seismic assessment was performed according to the NTC08 standards, evaluating the overall seismic response of the structure at Level LV3. A global structural model representing the building as-built was developed. This model allowed iterative calculation of the nominal life, risk indicators in terms of ground acceleration, and return periods. Prior to the verification procedures, a modal analysis of the structure was conducted to determine the most suitable analysis method for the building. The modal analysis confirmed the applicability of the equivalent linear static analysis model for this structure.

As required by Ordinance No. 3274/2003, a summary sheet of the seismic assessment for strategic buildings (relevant for civil protection or in the event of collapse due to a seismic event) was prepared – Department of Civil Protection, National Seismic Service (Ordinance No. 3274/2003 – Article 2, paragraphs 3 and 4; DM 14/01/2008).