Mechanically reinforced glass beams

The use of glass as a load carrying material in structural elements is rarely seen even though glass is a popular material for many architects. This is owed to the unreliable and low tensile strength, which is due to surface flaws and high brittleness of the material. These properties lead to breakage without any warning or ductility, which can be catastrophic if no precautions are taken. One aspect of this issue is treated here by looking at the possibility of mechanically reinforcing glass beams in order to obtain ductile failure for such a structural component. A mechanically reinforced laminated float glass beam is constructed and tested in four-point bending. The beam consist of 4 layers of glass laminated together with a slack steel band glued onto the bottom face of the beam. The glass parts of the tested beams are \SI{1700}{mm} long and \SI{100}{mm} high, and the total width of one beam is \SI{4\times10}{mm}. It is reinforced with a \SI{3}{mm} high steel band covering the full width of the beam. The experimental setup is described and results for this beam are presented. Furthermore, the results for three similar experiments with a \SI{6}{mm} steel band reinforcement are briefly presented. The experiments show that it is possible to obtain a very ductile structural behavior using the right amount of reinforcement. A Finite Element Model including - in a simple manner - the effects of cracking of glass is presented. Based on a comparison between experimental and model results the mechanical behavior of the beam is explained. Finally, some design criterions for reinforced glass beams are discussed.