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Residual load-bearing capacity of spannglass-beams: effect of post-tensioned reinforcement

Abstract

Reinforcement and pre-compression of concrete beams results in a ductile response and allows for the design of structures that are more reliable and efficient. Therefore, this approach has been adapted to structural glass producing reinforced and post-tensioned glass beams. Unbonded tendons in Spannglass Beams are one structural example for realising this idea and are the subject of the presented study. Two individual laminated safety glass packages connected locally by metal dividers characterise these beams. A gap between the packages was used to guide tendons in a either three- or a four-point bending configuration. This eccentric layout allowed for an initial uplift of the cross section and a mechanical pre-compression of the vulnerable glass edge. This was the primary objective during the initial design stage of the concept of Spannglass Beams. However, proving sufficient residual load-bearing capacity is a further requirement to ensure the safety of glass structures and requires additional study. During this stage, a common approach is to evaluate the effect of broken layers in the glass section, which may result in eccentric loading by the tendon and introduce additional bending about the minor axis. Thus, the novel structural design may cause an early (lateral) failure of the structure even during a service load condition. We examined a set of 16 Spannglass Beams with 5.0, 8.1 and 10.1 mm post-tensioned cables in an experimental study during four-point bending. Additionally, four un-reinforced specimens and four beams with untensioned tendons were tested. The paper includes a testing method to evaluate the residual load-bearing behaviour. First, the specimens were loaded in bending, after which a single glass layer was damaged manually by a hammer and a chisel. Finally, the assembly was left for 24 h before taking a next step to damage a consecutive layer. In this manner, it was possible to evaluate the residual load-bearing behaviour in terms of residual service-life as a function of damage scenario and load. Additionally, the crack pattern after each step, the evolvement of the deflection and the change in cable load were analysed before the final failure modes were characterised. This report aims to describe the effects of post-tensioning on the residual load-bearing capacity of glass beams. It was possible to influence the structural response considerably by reinforcing and post-tensioning glass beams. Due to excessive lateral deflection, an additional cable load reduced the residual service-life. However, the number of connectors in Spannglass Beams determined the shape during bending with a special focus on the buckling length and thus contributed to increasing the service-life as a major parameter during design. Finally, we derived structural recommendations for a future design of effective glass beams in facades, roofs or even “floating” glass bridges.

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References

  • Ahrens, C.G.: Katalog (2016). http://drahtseiltechnik.cgahrens.de/Kataloge-Downloads/Christian_G_Ahrens_Katalog.pdf. 18 Feb 2016

  • Bedon, C., Louter, C.: Numerical analysis of glass-FRP post-tensioned beams–review and assessment. Compos. Struct. 177, 129–140 (2017). https://doi.org/10.1016/j.compstruct.2017.06.060

    Article  Google Scholar 

  • CEN/TC 250/SC 11 prCEN/TS: Structural glass—design and construction rules. Part 1: Basis of design and material, 01 (2018) (working document)

  • Cupac, J., Martens, K., Nussbaumer, A., Belis, J., Louter, C.: Experimental investigation of multi-span post-tensioned glass beams. Glass Struct. Eng. (2017). https://doi.org/10.1007/s40940-017-0038-5

  • DIN 18008: Glass in building—design and construction rules. Parts 1–5, 2010–2013

  • Engelmann, M.: Spannglasträger–Glasträger mit vorgespannter Bewehrung (Spannglass Beams—Glass Beams with Post-Tensioned Reinforcement). Dissertation, Technische Universität Dresden (2017). http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-229676

  • Engelmann, M., Weller, B.: Post-tensioned glass beams for a 9 m spannglass bridge. Struct. Eng. Int. 26, 103–113 (2016). https://doi.org/10.2749/101686616X14555428759000

    Article  Google Scholar 

  • ETA-11/0160: Europäische Technische Zulassung/European Technical Approval ETA-11/0160: PFEIFER Seil-Zugglieder/Wire Ropes. Deutsches Institut für Bautechnik - DIBt (2011)

  • Härth, K.: Beitrag zum Tragverhalten hybrider Träger aus Glas und Kunststoff. Dissertation, Technische Universität Dresden (2013)

  • Hess, R.: Glasträger: Forschungsbericht. Bd. 20. vdf Hochschulverlag AG (2000)

  • Jordão, S., Pinho, M., Martin, J.P., Santiago, A.: Behaviour of laminated glass beams reinforced with pre-stressed cables. Steel Constr. 7(3), 204–207 (2014). https://doi.org/10.1002/stco.201410027

    Article  Google Scholar 

  • Kott, A.: Zum Trag- und Resttragverhalten von Verbundsicherheitsglas. Dissertation, Eidgenössische Technische Hochschule Zürich (2006)

  • Louter, P.C.: Fragile yet ductile: structural aspects of reinforced glass beams. Dissertation, Technische Universiteit Delft (2011)

  • Louter, P.C., Belis, J., Veer, F.A., Lebet, J.P.: Durability of SG-laminated reinforced glass beams: effects of temperature, thermal cycling, humidity and load-duration. Constr. Build. Mater. 27(1), 280–292 (2012). https://doi.org/10.1016/j.conbuildmat.2011.07.046

    Article  Google Scholar 

  • Louter, C., Cupac, J., Lebet, J.P.: Exploratory experimental investigations on post-tensioned structural glass beams. J. Facade Des. Eng. 2, 3–18 (2014). https://doi.org/10.3233/FDE-130012

    Google Scholar 

  • Martens, K., Caspeele, R., Belis, J.: Development of reinforced and posttensioned glass beams: review of experimental research. J. Struct. Eng. (ASCE) 142, 04015173 (2015). https://doi.org/10.1061/(ASCE)ST.1943-541X.0001453

    Article  Google Scholar 

  • Martens, K., Caspeele, R., Belis, J.: Performance of statically indeterminate reinforced glass beams. Experimental comparison with determinate systems and effect of a discontinuous glass section. Constr. Build. Mater. 146, 251–259 (2017). https://doi.org/10.1016/j.conbuildmat.2017.03.186

    Article  Google Scholar 

  • Schober, H., Gerber, H., Schneider, J.: Ein Glashaus für die Therme in Badenweiler. Stahlbau 73, 886–892 (2004). https://doi.org/10.1002/stab.200490213

    Article  Google Scholar 

  • Weller, B., Engelmann, M.: Deformation of spannglass beams subject to post-tensioning. In: Proceedings Challenging Glass 4—Conference on Architectural and Structural Applications of Glass (CGC4) & COST Action TU0905 Final Conference, Lausanne, Switzerland, pp. 285–294 (2014). https://doi.org/10.1201/b16499-42

  • Weller, B., Meier, A., Weimar, T.: Glass-steel beams as structural members of Façades. In: Proceedings of Challenging Glass 2—Conference on Architectural and Structural Applications of Glass (CGC2), Delft, Netherlands, pp. 517–524 (2010)

  • Weller, B., Engelmann, M.: Spannglasträger–Glasträger mit vorgespannter Bewehrung. Stahlbau 83, 193–203 (2014). https://doi.org/10.1002/stab.201490059

    Article  Google Scholar 

  • Zschippang, S., Wies, W., Weller, B., Shadow, T.: Glasdach Mensa und Rektorat der Technischen Universität Dresden. Stahlbau 75, 428–432 (2006). https://doi.org/10.1002/stab.200610044

    Article  Google Scholar 

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Acknowledgements

The research project was sponsored by the German Federal Ministry of Economics and Technology (BMWi) and was executed corporately with Thiele Glas Werk GmbH (Wermsdorf, Germany) and KL-megla GmbH (Eitorf, Germany). Additionally, PFEIFER Seil- und Hebetechnik GmbH (Memmingen, Germany) gave valuable support.

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Correspondence to Michael Engelmann.

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Michael Engelmann was formerly at Institute of Building Construction, Technische Universität Dresden, Dresden, Germany.

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Engelmann, M., Weller, B. Residual load-bearing capacity of spannglass-beams: effect of post-tensioned reinforcement. Glass Struct Eng 4, 83–97 (2019). https://doi.org/10.1007/s40940-018-0079-4

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Keywords

  • Glass beam
  • Reinforcement
  • Experimental investigation
  • Bending tests
  • Post-tensioning
  • Robustness
  • Post-fracture limit
  • Fracture safe