GNGTS 2022 - Atti del 40° Convegno Nazionale

GNGTS 2022 Sessione 2.2 307 In this study, the glass system considered has been the subject of in-depth analysis in a previous article (Mattei S. and Bedon C., 2021). In particular, the earlier analyses concerned FEM simulations by means the software Abaqus/CAE with the purpose of investigating its dynamic response and, through the application of Cloud analysis, of calculating specific component fragility curves. The main features of the non-structural glass component considered are summarized below: the glass panel is bounded to metal supports in aluminium (as shown in Fig. 1) on only two sides with adhesive joints; the materials are defined as perfectly elastic: σ t,glass = 45MPa and σ all = 235Mpa and the connection is modelled with axial connectors in the normal and tangential direction of the wire-to-ground type. In addition, stress values are monitored at each step of analyses in order to make the results of the FE analysis and numerical analysis consistent. In thiswork, a simplifiedmethod is presented, whichprovides an assessment of the response of the system under consideration and, thus, characterises it by means of fragility curves that can be used with a good approximation for the design of any glass panel by adapting the approach to specific cases, and then varying the oscillator parameters or also characterizing multi-degree of freedom systems through the respective equivalent SDOF. Then, in order to simplify and make even more immediate the derivation of fragility curves for glass building components, such systems can be converted into SDOF relying on the definition of Single- Degree of Freedom oscillator’s parameters and backbone parameters by a static pushover analysis on a three-dimensional model (i.e., Fig.1(b)). The latter should be able to reproduce the three main magnitudes of the system in seismic vibration in order to schematize it adopting as the only degree of freedom the horizontal displacement in the plane of the panel. Suppose that the mass is concentrated in a point and is subjected to the inertial force that is due to the application of an acceleration at the base, and in particular in correspondence of the bottom aluminium transom wedged to the substructure, the displacement is derived from the numerical resolution of the governing equations Eq. 2 and Eq. 3, through the Newmark Iterative Method. Seismic signals applied to the approximate system are the same as those used in nonlinear dynamic analyses on the FE three-dimensional model. In Fig. 2 are reported the maximum in-plane horizontal relative displacements as response to each accelerogram relative to the Fig. 1 - (a) Schematic representation of case-study and (b) backbone curve.