Structural analysis models for the assessment of seismic vulnerability of a masonry school building under new Italian rules (NTC 2018 and circular 2019)

As part of the "2nd program of seismic vulnerability assessments of Italian school buildings", the Carducci elementary school in Terni was audited. The school, completed in 1956, designed according to the regulations in force in 1954 and therefore not in an anti-seismic way, has an elongated rectangular plan, arranged transversely to a slight slope, with foundations on two levels, a partially basement floor and two floors outside land plus an attic. The school has a load-bearing masonry structure and has few, modest changes compared to the original project. In this work the procedure of the operations carried out for the evaluation of the seismic vulnerability is presented first: from the survey of the existing to the geotechnical characterization tests of the site, to the 3D modeling of the structure and design of the consolidation interventions. The first seismic vulnerability assessment was performed with reference to the Italian standards of 2008 and the 2009 explanatory circular. The results obtained, following a dynamic modal analysis with structural factor q, indicated the need to proceed with seismic consolidation operations that in the vulnerability assessment phase they were mainly proposed in the increase of the resistant capacity of the masonry walls. Subsequently, the executive project of the consolidation work was tendered out and today (2019), having completed the tender procedure, the consolidation work is in the start-up phase. After the entry into force of the new technical standards for construction (NTC2018) and the relative application Circular (February 2019) the impact of the innovations introduced in the field of existing masonry structures and in particular in the non-linear calculation was presented, both for the assessment of seismic vulnerability and for the planning of consolidation works. We then proceeded to a recalculation of the three-dimensional model of the entire building by comparing the results of linear static analysis, linear dynamic analysis and non-linear static analysis, also in relation to the planned interventions of consolidation. Finally, the economic effort of consolidation interventions is also presented.