Simplified structural analysis of laminated glass panels during fire exposure

Due to their high aesthetic value, energy-efficient properties, and contribution to daylighting, the demand for using glass panels in modern buildings has considerably increased over the past decades. However, ordinary glass panels are highly susceptible to cracking during a fire because of the temperature difference between the part of the glass exposed to the fire and the part protected by the frame. Damage to the glass can allow additional oxygen intake, leading to the flashover phenomenon significantly increasing fire severity. Laminated glass is superior to ordinary glass in its impact resistance, sound insulation, and ability to maintain post-breakage integrity. This paper provides a simplified method to study the effect of temperature gradients on the cracking behaviour of laminated glass panels. The temperature of the unprotected portion of the glass panel is first estimated by evaluating the mid-thickness temperature using the general heat transfer equation. Then, equations developed based on a parametric study that utilized ABAQUS are proposed to estimate the exposed and unexposed surface temperatures. This step was followed by evaluating the temperature of the protected glass portion. Subsequently, a method based on strain-equilibrium principles was developed to predict the corresponding maximum thermal stress. Comparisons with experimental and numerical work by others validated the proposed method.