Experimental Investigation on Post-tensioned Spannglass Beams during Temperature Loads

Recent research work focused on material efficient and safe structural use of glass beams. Reinforcing and post-tensioning of those structures in the style of reinforced concrete are promising options. They allow for a safe post-breakage behaviour of load bearing glass constructions. Other ductile m...

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Main Authors: M. Engelmann, P. Bukieda, B. Weller
Format: Article
Language:English
Published: Challenging Glass Conference 2016-06-01
Series:Challenging Glass Conference Proceedings
Subjects:
Online Access:https://proceedings.challengingglass.com/index.php/cgc/article/view/197
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author M. Engelmann
P. Bukieda
B. Weller
author_facet M. Engelmann
P. Bukieda
B. Weller
author_sort M. Engelmann
collection DOAJ
description Recent research work focused on material efficient and safe structural use of glass beams. Reinforcing and post-tensioning of those structures in the style of reinforced concrete are promising options. They allow for a safe post-breakage behaviour of load bearing glass constructions. Other ductile materials such as steel and high-grade cables strengthen the glass, which results in robust structures. However, hybrid structures are prone to temperature loads. Especially post-tensioned glass beams – Spannglass Beams – are vulnerable to lose part of their initial cable load caused by a different expansion of their parts. The thermal expansion coefficient of steel cables is about 70% larger than the value of glass. Therefore, a cable in a hybrid structure will expand much more during heating. This effect results in a loss in initial cable load of a post-tensioned reinforcement, and cannot be prevented. Hence, the temperature dependency needs to be considered during the design stage. Furthermore, a change in temperature influences the material properties of glass-contact materials and the interlayer. Thermoplastic blockings transfer the cable load into the laminated glass edge. Due to manufacturing tolerances, the interlayer material is stressed. Therefore, this will affect the reaction of the structure to a change in temperature. The non-destructive experimental study includes the results of a set of two Spannglass Beams with 8 mm post-tensioned cables. Adhesively bonded connectors redirect the cables according to the needs in a four-point bending set-up. Two-meter long beams were placed in a climate chamber to heat the specimens from ambient temperature to 60°C. We recorded the structural behaviour at alternating initial cable loads as well as different bending loads. Finally, the results led to a recommendation on how to consider a possible loss in cable load caused by a change in temperature. This will support the argumentation that post-tensioning glass beams is a feasible structural option.
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spelling doaj.art-e52eeac3bb6e4dbd8ebb2f5fc4deb2822022-12-21T23:28:24ZengChallenging Glass ConferenceChallenging Glass Conference Proceedings2589-80192016-06-01510.7480/cgc.5.2242183Experimental Investigation on Post-tensioned Spannglass Beams during Temperature LoadsM. Engelmann0P. Bukieda1B. Weller2Technische Universität Dresden, Institute of Building ConstructionTechnische Universität Dresden, Institute of Building ConstructionTechnische Universität Dresden, Institute of Building ConstructionRecent research work focused on material efficient and safe structural use of glass beams. Reinforcing and post-tensioning of those structures in the style of reinforced concrete are promising options. They allow for a safe post-breakage behaviour of load bearing glass constructions. Other ductile materials such as steel and high-grade cables strengthen the glass, which results in robust structures. However, hybrid structures are prone to temperature loads. Especially post-tensioned glass beams – Spannglass Beams – are vulnerable to lose part of their initial cable load caused by a different expansion of their parts. The thermal expansion coefficient of steel cables is about 70% larger than the value of glass. Therefore, a cable in a hybrid structure will expand much more during heating. This effect results in a loss in initial cable load of a post-tensioned reinforcement, and cannot be prevented. Hence, the temperature dependency needs to be considered during the design stage. Furthermore, a change in temperature influences the material properties of glass-contact materials and the interlayer. Thermoplastic blockings transfer the cable load into the laminated glass edge. Due to manufacturing tolerances, the interlayer material is stressed. Therefore, this will affect the reaction of the structure to a change in temperature. The non-destructive experimental study includes the results of a set of two Spannglass Beams with 8 mm post-tensioned cables. Adhesively bonded connectors redirect the cables according to the needs in a four-point bending set-up. Two-meter long beams were placed in a climate chamber to heat the specimens from ambient temperature to 60°C. We recorded the structural behaviour at alternating initial cable loads as well as different bending loads. Finally, the results led to a recommendation on how to consider a possible loss in cable load caused by a change in temperature. This will support the argumentation that post-tensioning glass beams is a feasible structural option.https://proceedings.challengingglass.com/index.php/cgc/article/view/197glass beampost-tensioningreinforcementtemperature loadtemperature compensationspannglass
spellingShingle M. Engelmann
P. Bukieda
B. Weller
Experimental Investigation on Post-tensioned Spannglass Beams during Temperature Loads
Challenging Glass Conference Proceedings
glass beam
post-tensioning
reinforcement
temperature load
temperature compensation
spannglass
title Experimental Investigation on Post-tensioned Spannglass Beams during Temperature Loads
title_full Experimental Investigation on Post-tensioned Spannglass Beams during Temperature Loads
title_fullStr Experimental Investigation on Post-tensioned Spannglass Beams during Temperature Loads
title_full_unstemmed Experimental Investigation on Post-tensioned Spannglass Beams during Temperature Loads
title_short Experimental Investigation on Post-tensioned Spannglass Beams during Temperature Loads
title_sort experimental investigation on post tensioned spannglass beams during temperature loads
topic glass beam
post-tensioning
reinforcement
temperature load
temperature compensation
spannglass
url https://proceedings.challengingglass.com/index.php/cgc/article/view/197
work_keys_str_mv AT mengelmann experimentalinvestigationonposttensionedspannglassbeamsduringtemperatureloads
AT pbukieda experimentalinvestigationonposttensionedspannglassbeamsduringtemperatureloads
AT bweller experimentalinvestigationonposttensionedspannglassbeamsduringtemperatureloads