Hybrid laminated-glass plate: Design and assessment

This paper is focused on laminated glass plate designed with the “sacrificial ply” concept: The glass layer that collects the live loads is considered as broken (i.e., it is not considered), independently of whether or not it is fractured. Accordingly, the load-bearing system is composed of: Heath-strengthened (or annealed) glass layer, plus interlayer, plus toughened (tempered, or chemically-strengthened) glass layer. Hence, the laminated glass plate is hybrid. The first part of the paper derives the constitutive law of the interlayer materials that belong to the latest generation. Then, the behavior of the laminated glass plate is predicted by using this new constitutive law in lieu of the constitutive law of traditional interlayer materials, and the results are analyzed. The second part discusses the results of a theoretical analysis conducted on products available on the architectural marketplace that encompass glass structural applications. These results prove that the ultimate load is dictated by the toughened glass only if the stiffness of the interlayer surpasses a critical value; otherwise, it is dictated by the less resistant glass. However, the critical value is very high. Moreover, the results prove that assessment cannot use practical or simplified expressions (e.g., effective thickness), since these expressions provide the maximum stress in the plate but not in each layer.