• Special Issues
  • NUMERICAL AND EXPERIMENTAL ASSESSMENT OF THE PERFORMANCE OF FOUR NONDESTRUCTIVE DAMAGE EVALUATION METHODS IN SITUATIONS COMPARABLE TO POST-EARTHQUAKE DAMAGE ANALYSIS

    This study evaluates several methods for the detection and location of a perturbation along a bending beam. Unlike previous studies, the situation chosen is comparable to that encountered in-situ after an earthquake. Indeed, assessment of earthquake damage to buildings is a crucial factor in crisis management. Buildings can be tested appropriately using operational modal analysis methods based on ambient vibration data. In this study, we tested four modal-based methods to locate the perturbation. The mode shapes and eigenfrequencies of a beam were evaluated in the laboratory using the frequency domain decomposition method applied to ambient vibrations simulated along a one-dimensional bending beam, using the finite element method and recorded on a poly(methyl methacrylate) (Plexiglas) beam-like free-clamped structure. The data show that the uniform load surface curvature method is the most efficient, and it allows for accurate estimation of the location of the perturbation, whatever its nature (e.g., multiple, simple, different positions). The experimental data also show that frequency domain decomposition resolution of the mode shapes must be as accurate as possible, otherwise it is impossible to locate transient perturbations over short periods.

     

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  • Uncategorized
  • The Mapping of Post-Earthquake Damage Scenarios in Support of Municipal Emergency Plans

    Nel presente lavoro viene proposta una metodologia, chiamata SCE-PEC, per la rappresentazione di scenari di danno post-sisma /1/, finalizzati agli obiettivi della pianificazione comunale dell’emergenza sismica /2,3/. Uno scenario di danno post-sisma contiene informazioni essenziali per la pianificazione delle attività delle Funzioni di Supporto /4,5/. Detta metodologia utilizza vari tipi di mappe con differenti livelli di elaborazione e sintesi: mappe di base, mappe di danno, mappe di sintesi e mappe per funzioni di supporto. La metodologia SCE-PEC è di tipo modulare e pertanto è possible applicarla parzialmente o integrarla con infor- mazioni aggiuntive.

    For this paper is available an extended abstract after the text in Italian

  • Uncategorized
  • Lo studio di interventi antisismici tramite analisi dinamiche con un modello ad elementi rigidi: il caso del Castello Maniace

    A specific numerical model is proposed for the in-plane dynamical analysis of a masonry monument, with particular attention to the design of interventions for seismic protection. In order to perform effective compu- tational analyses, the present model is conceived to operate at the macro-scale considering the energy dissipation capacity of the masonry material, as well as the effects of the masonry texture on the local damage mechanisms. In particular, the model was implemented according with a mechanistic point of view, in the spirit of the rigid body and spring model approach, RBSM. In the present application we describe the passage from the global three dimensional model of the Maniace Castle in Syracusae to the identification of the specific collapse mechanism that is more at risk, and that can be specifically described by means of a plane model. Then, the dynamics of a transversal cross-section of the hypostyle salon of the Castle is investigated with particular attention to the enhancement of the seismic response that can be achieved by an intervention of rebuilding and reshaping of the buttresses.

    This paper is available in Italian only.