GNGTS 2022 - Atti del 40° Convegno Nazionale

250 GNGTS 2022 Sessione 2.2 Regarding the in-plane displacement capacity (inter-story drift accommodation), finally, this was set in u lim,in = 0.005 H = 45 mm (with H = 9 m the total height of storey / building). Results of local seismic analysis . The seismic performance of the glass envelope was numerically investigated by means of monotonic, linear application of an in-plane lateral force at the top of the envelope frame ( F ), as well as of an equivalent uniformly distributed pressure (Q). This is in line with CNR-DT 210/2013 provisions, where local verification is allowed for secondary glass elements belonging to primary buildings. Overall, the attention was focused on the analysis of stress evolution and peaks in glass components, as well as on the deformation trends under seismic action. In Fig. 3, major trends of seismic response can be noticed. Figs. 3(a) and (b), in particular, represent the principal stress in glass and the out-of-plane glass deflection under the imposed in-plane seismic loads F . It can be seen, as also proposed in Figs. 3(d) and (e), the critical role of glass edges, which are subjected to major stress peaks. According to performance indicators as in Section 3, the present envelope would be able to accommodate a maximum in-plane displacement up to ≈0.0001 H , thus rather small compared to current requirements. As far as the local seismic analysis is carried out in terms of out-of-plane equivalent pressure Q , see Fig. 3(c), maximum stress peaks are still achieved at the edges of central glass panel. The uniform pressure the system could resist is in this case in the order of ≈0.2 kN/m 2 . The out-of-plane displacement for Q = 1kN/m 2 was measured in around a maximum of ≈20 mm, which is still far away from the reference limit value. Conclusions and future developments . The present results show that the region of edges is particularly critical for glass panels, both when exposed to in-plane or out-of-plane design actions. For the examined case-study system, a major issue was represented by the use of relatively thin glass components (monolithic elements with 5 mm in thickness) which were not specifically conceived to provide any kind of load-bearing capacity or seismic resistance and displacement accommodation. In this sense, a strong limitation affecting the possible Fig. 3 - Seismic performance assessment based on local analysis (as from CNR-DT 210/2013): (a)-(b) maximum principal stress and out-of-plane deflection under in-plane seismic load, with (d)-(e) example of corresponding contour plot (legend values in Pa and m), and (c) principal stress under out-of-plane seismic load, with (f) corresponding distribution (ABAQUS).