Experimental investigation of multi-span post-tensioned glass beams

Abstract

This paper presents a study on posttensioned glass beams in a statically indeterminate system. In order to increase the safety of structural glass beams, ductile reinforcement can be added to glass beam sections providing secondary load carrying mechanism in case of glass breakage. In the here investigated post-tensioned system, the reinforcement tendons are additionally pre-tensioned, introducing compressive pre-stress in the beam in order to increase the apparent tensile strength of glass. The system is tested in five-point bending at 23 and 60 • C in order to investigate the basic structural performance and the influence of temperature increase on the initial cracking load and the behaviour of the cracked beam. The benefit of the here investigated statically indeterminate system is a more economical design, i.e. lowering of the bending moment in the span of an equivalent simply supported system by continuing the beam over the central support. The efficiency of the applied system is compared to a reinforced beam system produced in the same batch with similar overall dimensions. The results show an increase of initial cracking load of the post-tensioned beams due to the applied pre-stress and a ductile post-cracking response, reaching high ultimate loads prior to failure. At 60 • C both reinforced and post-tensioned beams show lower initial cracking loads and limited post-cracking ductility but still significant load reserve with ultimate loads well above the initial cracking loads, providing safe failure behaviour.

Mechanical prestressing of annealed glass beams using pretensioned GFRP: Characterisation and potentiality

“…Mechanical prestressing of glass beams and tension glass members using steel prestressing tendons/strips (e.g. [12][13][14][15][16][17][18]), a concept similar to prestressing (i.e. post-tensioning) of concrete beams [e.g.…”

“…Then, a compressive prestress was introduced into glass by transferring the force in the tendons into glass through specially designed end-connectors fixed at the end of the glass beams (e.g. [18]). Despite the simplicity of the concept, insufficient prestress transfer into the glass beams, premature failures caused by the misalignment between the end-connectors and the glass beams, and lateral buckling of glass beams during prestressing hamper the practical feasibility of the mechanically-anchored glass prestressing systems.…”

Vorbild Spannbeton: Glasträger nach Eurocode 2

“…In allen gezeigten Fällen wurde neben einer gesteigerten Erstrisslast auch ein duktiles Verhalten im weiteren Belastungs‐ und Rissverlauf festgestellt, sodass die erfolgversprechenden Resultate eine Erweiterung der Untersuchung auf Durchlaufträger motivierten (Bild d) . Als wesentliche konstruktive Herausforderung musste die Vorspannkraft materialgerecht in eine unebene Verbundglaskante eingeleitet werden, wodurch mitunter ein frühzeitiger Riss im Bereich der Lasteinleitung ausgelöst wurde.…”

The TVT Glass Pavilion: Theoretical Study on a Highly Transparent Building Made with Long-Spanned TVT Portals Braced with Hybrid Glass-Steel Panels

“…In particular, active pre-stressed beams showed excellent performance: these include beams with a single [8,9] or double [10] glass web reinforced with external tendons, beams with metallic reinforcement adhesively [11][12][13] or mechanically [14] bonded at the bottom side, and two-sided reinforced glass beams [15,16]. Concerning two-dimensional systems, hybrid solutions are less diffuse than hybrid beams even though glass as a shear frame restraint has been used since the nineteenth century (i.e.…”