S. Maria school in Livigno (SO) – seismic hazard analysis

The building is made up of a main section from 1954 and an extension from 1981.

The geological-geometrical analysis aimed at characterizing the area adjacent to the building for seismic risk factor in agreement with the Italian national and regional Seismic Code, with additional indication concerning the rocky sub-stratus below the building. The following operations were therefore carried out:

- refraction seismic testing to identify the average depth of the rocky sub-stratus;
- MASW analysis– ReMi to calculate VS30 parameters as the average speed of cut wave propagation (S) within 30 metres depth;
- H/V analysis for seismic resonance testing and to build up an estimate of the frequency with which earth movement can be amplified by these phenomenons.

Investigation provided an LC3 level of accuracy in structural knowledge. Testing was carried out on the most important structural elements referring to the original construction plan data, although only partially available. Where detailed plans were not available, the elements were thoroughly analysed. Some original information was available for certain materials used, where such was not available further on site checks were carried out

The activity was performed following this operational programme:
•structural documentation analysis;
•testing with integration of any areas not conforming to the project;
•magnetometric survey of rebars;
•concrete coring for compression testing in the laboratory;
•ultrasound velocity measurements for detecting the homogeneity of the concrete and to determine the  mechanical resistance;
•measurement of carbonatation depth;
•laboratory traction testing on rebars;
•flat jack stress testing on masonry structures;
•parallel flat jack testing for masonry deformability and its compression resistance;
•surveys to detect the details of the main structural elements.

In compliance with the Italian Seismic Code the assessment of the seismic resistance was carried out with a full review of seismic hazard factor according to level LV3.
Thus, a structural model was constructed allowing for the calculation of nominal impact, risk factors in terms of acceleration over solid ground and shock reverberation
Prior to testing, the structural modal analysis was performed to identify the analysis that best suits the structure. 
The modal analysis allowed for the checking of adaptability in the static linear analysis model equating to the structure in question.