Citation: Honfi, D.; Sjöström, J.; Bedon, C.; Kozlowski, M. Experimental and Numerical Analysis of Thermo-Mechanical Behaviour of Glass Panes Exposed to Radiant Heating. Fire 2022, 5, 124. https://doi.org/10.3390/fire5040124 Academic Editor: Alistair M. S. Smith Received: 22 July 2022 Accepted: 17 August 2022 Published: 20 August 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). fire Article Experimental and Numerical Analysis of Thermo-Mechanical Behaviour of Glass Panes Exposed to Radiant Heating Dániel Honfi 1 , Johan Sjöström 1 , Chiara Bedon 2, * and Marcin Kozlowski 3,4 1 RISE Research Institutes of Sweden, 412 58 Gothenburg, Sweden 2 Department of Engineering and Architecture, University of Trieste, 34127 Trieste, Italy 3 Department of Structural Engineering, Silesian University of Technology, 44 100 Gliwice, Poland 4 Faculty of Engineering LTH, Lund University, 221 00 Lund, Sweden * Correspondence: chiara.bedon@dia.unists.it; Tel.: +39-040-558-3837 Abstract: Despite much research and applications, glass material and its use in buildings is still challenging for engineers due to its inherent brittleness and characteristic features such as sensitivity to stress concentrations, reduction in strength over time and from temperature, and breakage due to the stresses that may build up because of thermal gradients. This paper presents the results of an original test series carried out on monolithic glass panes with the dimensions of 500 × 500 mm 2 and different thicknesses, under the exposure to radiant heating. The research study also includes a one- dimensional (1D) heat transfer model and a numerical, three-dimensional (3D) thermo-mechanical model that are used to investigate in greater detail the phenomena observed during the experiments. As shown, the behaviour of glass under radiant heating is rather complex and confirms the high vulnerability of this material for building applications. The usability and potential of thermo- mechanical numerical models is discussed towards experimental feedback. Keywords: structural glass; structural fire safety; finite element modelling; thermo-mechanical modelling 1. Introduction 1.1. Background A recent trend in modern architecture is to provide maximum transparency to the building interior by reducing visual obstructions of the structural frame and envelope [1]. This movement includes the increased use of self-supporting glass structural elements and large glass panels for the façade of the buildings. Glass has rapidly developed from an infill to a structural material, thus enabling engi- neers to design and build walls, beams, columns, floors, stairs, etc., and use spans and large transparent areas that have not been possible before. A well-known example of maximising transparency is the Apple store on Fifth Avenue in Manhattan (see Figure 1). However, the structural design of glass is still challenging, e.g., due to its inherent brittleness, sensitivity to stress concentrations, reduction in strength over time, and possible thermal breakage [2]. Furthermore, several other issues in relation to safe and economical structural design can be accounted to the relatively common degradation of materials used in combination with glass (due to severe humidity and temperature variations, or unfavourable operational conditions for vibrations, etc.). There are methods and solutions to improve the robustness of glass structural applica- tion, including increasing the strength of glass, such as thermal treatment, pre-stressing, edge polishing, and preventing, or mitigating the risks of brittle failure, e.g., by careful detailing, lamination, composite members, backup systems, provision of alternative load paths, etc. [3]. Exceptional situations, such as elevated temperature during a building fire, are challenging and require further considerations of such robustness measures to ensure the safety of the building occupants and allow for evacuation [4]. The primary Fire 2022, 5, 124. https://doi.org/10.3390/fire5040124 https://www.mdpi.com/journal/fire