GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 2.2 GNGTS 2024 The movement of a glass panel within the frame can be summarized as in Fig. 2(c) (Sucuoǧlu & Vallabhan, 1997): 1. Rigid horizontal movement of the panel unCl the contact with the frame. 2. The contact happens in two opposite glass corners and the panel start to rotate. 3. When the two opposite glass panel corners make contact with those of the surrounding frame, the panel acts like a diagonal strut. The final configuraCon may result in either a compressive crushing failure or the pracCcally intact glass panel falling out due to the loss of support on the contour. Fig. 3(a) and (b) show the deformed shape of the “fixed” and “isolated” models at the maximum imposed displacement. The effect of the adopted isolaCon system is evident and corresponds to a major reducCon in the frame deformaCon, as well as a decrease in its absolute in-plane lateral displacement. The laber is also highlighted by Fig. 3(c), where the displacement of the same control point is reported for the two configuraCons. The reducCon corresponding to the maximum imposed displacement is - 67%. Such a major decrease in the in-plane bending frame deformaCon naturally leads to a reducCon of stress peaks in both metal and glass components, as Fig. 3(d) shows. In this case, the stress reducCon corresponding to the maximum imposed displacement is quanCfied in - 99%. As shown in Fig. 2(c), breaking of the glass or its fall-out depends to the contact with the frame. Fig. 3(e) shows the relaCve distance between two joints, one from a glass panel and one from the frame, connected with a link. Fig. 3(e) shows a constant relaCve distance for the “isolated” model, equal to the iniCal clearance of 6 mm. This confirms the possibility of avoiding glass failure adopCng the seismic isolaCon system presented. AddiConally, Fig. 3(e) highlights an intrinsic limitaCon of the modelling strategy adopted for the “fixed” model in the local performance assessment as the relaCve distance becomes negaCve. Conclusions Due to brible behaviour of glass, façades are vulnerable building components, especially under extreme acCons, such as earthquakes. In this paper, preliminary consideraCons and numerical results about the effects of a seismic isolaCon system inspired by rubber seismic isolators are presented. The abenCon was given primarily to reducCon in displacement and stress peaks through a comparison between the numerical results of an experimental tested glass façade and the same GCW equipped with the isolaCon system. In this regard, a - 67% reducCon in maximum frame displacement and a - 99% reducCon in peak frame stress was recorded. In addiCon, the absence of relaCve displacement between glass and frame was noted for the “isolated” façade. In this sense, the analysis of present results confirms the posiCve effects of such a system in reducing damage of GCWs subjected to in-plane lateral displacement.