Despite significant research advances on the seismic response analysis, there is still an urgent need for validation of numerical simulation methods for prediction of earthquake response and damage. In this respect, seismic monitoring networks and proper modelling can further support validation studies, allowing more realistic simulations of what earthquakes can produce. This paper discusses the seismic response of the “Pietro Capuzi” school in Visso, a village located in the Marche region (Italy) that was severely damaged by the 2016–2017 Central Italy earthquake sequence. The school was a two-story masonry structure founded on simple enlargements of its load-bearing walls, partially embedded in the alluvial loose soils of the Nera river. The structure was monitored as a strategic building by the Italian Seismic Observatory of Structures (OSS), which provided acceleration records under both ambient noise and the three mainshocks of the seismic sequence. The evolution of the damage pattern following each one of the three mainshocks was provided by on-site survey integrated by OSS data. Data on the dynamic soil properties was available from the seismic microzonation study of the Visso village and proved useful in the development of a reliable geotechnical model of the subsoil. The equivalent frame (EF) approach was adopted to simulate the nonlinear response of the school building through both fixed-base and compliant-base models, to assess the likely influence of soil–structure interaction on the building performance. The ambient noise records allowed for an accurate calibration of the soil–structure model. The seismic response of the masonry building to the whole sequence of the three mainshocks was then simulated by nonlinear time history analyses by using the horizontal accelerations recorded at the underground floor as input motions. Numerical results are validated against the evidence on structural response in terms of both incremental damage and global shear force–displacement relationships. The comparisons are satisfactory, corroborating the reliability of the compliant-base approach as applied to the EF model and its computational efficiency to simulate the soil–foundation–structure interaction in the case of masonry buildings.

The construction of reliable numerical models is a key aspect within the seismic assessment of existing unreinforced masonry buildings. However, it is also a complex process due to the many uncertainties involved that can affect the structural response. In situ tests allow for the acquisition of data at a local scale. Nonetheless, supplementary information representing the global response is necessary to overcome other uncertainties (i.e., wall-to-wall connections or floor stiffness). To this end, data from ambient vibration tests (AVT) are useful to support seismic assessments. In fact, they allow for the identification of dynamic structural properties, which are useful in refining the calibration of numerical models. In addition, they address solutions for the aforementioned uncertainties. In this context, the paper presents how to efficiently exploit AVT data by using the case study of the former Courthouse of Fabriano (Ancona, Marche). This structure has been monitored since 2010 by the Italian Department of Civil Protection with a network of 28 seismic accelerometers. As a result, the equivalent frame (EF) model was calibrated in the linear field thanks to the dynamic identification provided under operational conditions. Subsequently, nonlinear dynamic analyses were performed using the recordings acquired during the Central Italy earthquake in 2016/2017. Even if the building experienced only a slight nonlinear behaviour, this comparison between the simulated and actual seismic response made it possible to validate the EF model, especially with reference to the capability in reproducing the amplification phenomena, which is extremely important for the assessment of structural and non-structural components. K E Y W O R D Sdynamic identification, equivalent frame models, masonry structures, permanent monitoring, recordings from seismic eventsThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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The paper discusses the effects of Soil-Foundation-Structure (SFS) interaction on the seismic response of the "Pietro Capuzi" school in Visso, a village located in the Marche region (Italy) that was severely damaged by the 2016-2017 Central Italy seismic sequence. The school is a two-story masonry structure founded on simple enlargements of its loadbearing walls, which are only partially embedded in the alluvial loose soil of the Nera river. The structure was monitored as a strategic building by the Italian Seismic Observatory of Structures. The dynamic behavior of the school under both ambient noise and the recently occurred seismic events was interpreted and compared with numerical simulations. A 3D structural model of the school was realized according to the equivalent frame approach with addition of springs that simulate a compliant base. The spring stiffness, representing the real part of soilfoundation dynamic impedance, was calibrated on the soil shear modulus mobilized during the seismic excitation, inferred from the deconvolution up to the bedrock of the accelerogram recorded at the underground floor of the school. The amplitude of the acceleration and the evolution with time of the frequency resulted from the analyses of the compliant-base and fixed-base models under the three main events of the Central Italy earthquake were compared to the actual records.

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