Numerical investigation of two-sided reinforced laminated glass beams in statically indeterminate systems

A significant number of investigations has been performed to improve the unsafe (brittle) failure behaviour of glass beams. Similar to reinforced concrete, reinforced glass beams have been developed in which stainless steel is embedded in the glass laminate to obtain safe failure behaviour. The concept has been proven to be feasible when assuming statically determinate systems. However, the additional system safety of statically indeterminate systems has not been investigated yet. This paper presents numerical research outcomes on reinforced glass beams with statically determinate as well as statically indeterminate support conditions. In a first step, a model of a two-sided reinforced beam subjected to three-point bending was created for validation purposes. The thickness and height of the constituents making up the model were based on experimental measurements of test specimens. Subsequently, the same numerical model was made using nominal dimensions for the glass and reinforcement. In this way, the effect of dimensional tolerances on the load-carrying behaviour was investigated. Furthermore, a single-sided reinforced glass beam was modelled under the same loading conditions to assess the effect of adding compressive reinforcement. In a second step, statically indeterminate two-sided reinforced beam models were constructed based on the statically determinate model. From these preliminary models, the load-carrying behaviour and effect of reinforcement percentage were evaluated. Finally, also the stress redistribution capacity of both beam models was assessed. It is concluded that dimensional tolerances have a significant effect on the load-carrying behaviour and should therefore be accounted for in the design of reinforced glass beams. The additional compressive reinforcement provides slightly higher bending stiffness, initial failure load and yield load to the glass beams, although it does not contribute in the yield phase. However, a different ultimate collapse mechanism is expected as the compressive reinforcement can take the stress when the glass compressive zone has failed. The statically indeterminate simulations proved the feasibility of applying reinforced glass beams in statically indeterminate systems as a safe failure behaviour was observed with significant stress redistribution capacity. Changing the reinforcement percentage has a significant effect on the load-carrying behaviour of these systems. However, the overall behaviour remains safe.