The bending strength of flat glass panels including the effects of their edges, is commonly determined by means of the four-point bending test method. This is an established and reliable method. However, when testing glass thinner than 3 mm, large deformation may occur. This means that the calculated stresses might not correspond to the actual, as the hypothesis behind the small deformation theory does no longer hold. Furthermore, it might occur that the specimen slips out of the supports, compelling the testing impossible. An alternative method, suitable for thin glass, consists of inducing an increasing curvature from flat until fracture. The curvature is to be constant along the length of the specimen at any time. The stress at fracture is calculated by knowing the corresponding radius or the applied bending moment. The equipment capable of performing this test is the clamp bender whereby the glass is held by two clamps at the specimen's ends. Rotational and translational movement combine to uniaxially bend the glass as desired. This paper explores the validity of the clamp bender for testing thin glass M. Zaccaria (B) • N.

Chemically strengthened glass is commonly used for applications that require high strength, such as boat and train windshields, control towers and the like. The strengthening process provides the glass with a surface residual stress that outperforms other strengthened glass types, such as thermally toughened glass. However, its use has been limited, probably for two main reasons: its high cost compared to other strengthening method and the perceived loss of the strengthening if glass surface is damaged. With the recent developments in the field of thin glass, where chemical strengthening is the only possible pre‐stressing method, there is the opportunity to better understand the process and the procedure to make it a safe material for architectural applications. In this paper, an extensive investigation on chemically strengthened glass is presented. Different parameters are considered, such as different thicknesses and chemical strengthening process conditions. The work consists of photoelastic measurement and destructive test. The data arising from the tests are elaborated with the purpose of suggesting a method to calculate the design strength of chemically strengthened glass according to the existing design standards. It is highlighted the importance to qualify chemically strengthened glass in terms of its residual stress profile.