Damage in glass-concrete composite panels

The evolution of damage of a glass-concrete façade panel is presented and discussed. The phenomenon is strongly influenced by the mutual interaction between three materials (concrete, steel rebars and glass) having different mechanical and rheological properties. To assess the possible causes of the observed damages, detailed 3D finite element numerical analyses were conducted considering the effects of thermal loads, due to difference of temperature outside and inside of the building, and the effects of concrete shrinkage. Furthermore, a construction stages analysis was implemented to consider the loading history during the production process of the panel. The analyses were performed both in linear elastic and non-linear conditions to assess the stress redistributions in the panel due to concrete cracking. In particular, the analyses showed that the shrinkage of concrete was the main reason of the detected damage in a case study, even considering the creep that mitigates the phenomenon leading to a delayed cracking. Finally, a parametric study is presented assuming different factors (concrete rib sizes, different shrinkage laws, as a consequence of the addition of shrinkage-reducing admixtures (SRA), different bond between glass and concrete and different reinforcement ratio). The results of this parametric study suggest interesting remarks about suitable design principles of glass-concrete façade panels.