Steel-Reinforced Columns Made of European Beech Glued-Laminated Timber
Publication: Journal of Structural Engineering
Volume 150, Issue 2
Abstract
One of the obstacles to the recent trend toward taller timber buildings is the limited load-carrying capacity of softwood columns. With the aim of promoting the structural use of European beechwood (Fagus sylvatica L.) in high-performance applications, the buckling behavior of beech glued-laminated timber (GLT) columns reinforced with glued-in steel bars was investigated experimentally and numerically. Axial compression experiments were carried out on full-scale stocky and slender columns, and a finite-element model was developed and validated against the experimental data. The influence of geometric and material parameters on the load-carrying capacity of the steel-reinforced beech GLT columns was studied in parametric analyses. The experimental and numerical data demonstrate the high potential of this new structural product for high-strength columns in demanding residential, office, and industrial applications. The load-carrying capacity mainly depends on the cross section size, the column slenderness, the position and diameter of the reinforcement bars, and the initial deformed shape of the column. An eccentric layout with steel bars in the corners of the cross section is very effective in increasing the load-carrying capacity. Four corner steel bars of 20 mm diameter, 50 mm edge distance, and grade ST900/1100 were found to increase the load-carrying capacity of a 200-mm-wide square GL48h column by almost 40% across the slenderness ratios relevant to structural applications. The glued-in steel reinforcement is also expected to be able to provide an alternative load path for structural robustness, by enabling the columns to carry tensile forces. A design method for corner-reinforced beech GLT columns under axial compression was developed based on the empirical and numerical data.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request. Some or all data, models, or code generated or used during the study are proprietary or confidential in nature and may only be provided with restrictions. The experimental data are proprietary and confidential, and availability is subject to approval and restrictions by the company neue Holzbau AG.
Acknowledgments
The company neue Holzbau AG produced and supplied the test specimens and contributed to the costs for carrying out the experiments.
References
Abplanalp, B., T. Strahm, and T. Rohner. 2019. Einsatz von Buchen-Brettschichtholz in hochbelasteten Anwendungen: Demonstrationsobjekt [Beech glued-laminated timber in highly stressed applications: Demonstration object]. [In German.]. Lungern, Switzerland: neue Holzbau AG.
Abrahamsen, R. 2017. “Mjøstårnet-construction of an 81 m tall timber building.” In Proc., 23. Internationales Holzbau-Forum (IHF). Biel, Switzerland: Forum Holzbau.
Blaß, H. J. 1987. “Tragfähigkeit von Druckstäben aus Brettschichtholz unter Berücksichtigung streuender Einflussgrössen” [Load-carrying capacity of compression members made from glued-laminated timber, accounting for scatter of influencing variables]. [In German.] Ph.D. thesis, Dept. of Timber Structures and Building Construction, Karlsruhe Institute of Technology.
Blaß, H. J. 1995. “Buckling lengths.” In Timber engineering–STEP 1, B7/1–8. Almere, Netherlands: Centrum Hout.
BMEL (Federal Ministry of Food and Agriculture). 2023. “Ergebnisse der Waldzustandserhebung 2022” [Results of the forest status survey 2022]. In Division 515–Sustainable forest management, timber market, [In German.] Bonn, Germany: BMEL.
Bohannan, B. 1962. “Prestressing wood members.” For. Prod. J. 12 (12): 596–602.
Borgin, K. B., G. F. Loedolff, and G. R. Saunders. 1968. “Laminated wood beams reinforced with steel strips.” J. Struct. Div. 94 (7): 1681–1705. https://doi.org/10.1061/JSDEAG.0002011.
Bulleit, W. M. 1980. “Behavior of fiberglass reinforced particleboard beams and plates in flexure.” Ph.D. thesis, Dept. of Engineering Science, Washington State Univ.
Bulleit, W. M. 1981. “Models for reinforced particleboard in flexure.” In Proc., 15th Washington State University Int. Symp. on Particleboard. Pullman, WA: Washington State Univ.
Bulleit, W. M. 1984. “Reinforcement of wood materials: A review.” Wood Fiber Sci. 16 (3): 391–397.
Bulleit, W. M., L. Sandberg, and G. Woods. 1989. “Steel-reinforced glued laminated timber.” J. Struct. Eng. 115 (2): 433–444. https://doi.org/10.1061/(ASCE)0733-9445(1989)115:2(433).
CEN (European Committee for Standardization). 2004a. Eurocode 5: Design of timber structures—Part 1-1: General—Common rules and rules for buildings. EN 1995-1-1:2004. Brussels, Belgium: CEN.
CEN (European Committee for Standardization). 2004b. Eurocode 5: Design of timber structures–Part 1-2: General—Structural fire design. EN 1995-1-2:2004. Brussels, Belgium: CEN.
CEN (European Committee for Standardization). 2012. Timber structures—Structural timber and glued laminated timber—Determination of some physical and mechanical properties. EN 408:2012. Brussels, Belgium: CEN.
CEN (European Committee for Standardization). 2016. Structural timber—Strength classes. EN 338:2016. Brussels, Belgium: CEN.
Corradi, M., A. I. Osofero, and A. Borri. 2019. “Repair and reinforcement of historic timber structures with stainless steel–A review.” Metals 9 (1): 106. https://doi.org/10.3390/met9010106.
De Luca, V., and C. Marano. 2012. “Prestressed glulam timbers reinforced with steel bars.” Constr. Build. Mater. 30 (May): 206–217. https://doi.org/10.1016/j.conbuildmat.2011.11.016.
Ehrhart, T. 2019. “European beech glued laminated timber.” Ph.D. thesis, Dept. of Civil, Environmental and Geomatic Engineering, ETH Zürich.
Ehrhart, T., G. Fink, R. Steiger, and A. Frangi. 2016. “Strength grading of European beech lamellas for the production of GLT & CLT.” In Proc., Int. Network on Timber Engineering Research (INTER)–Meeting 49, 49-5-1. Karlsruhe, Germany: Timber Scientific Publishing, KIT Holzbau und Baukonstruktion.
Ehrhart, T., R. Steiger, A. Frangi, G. Clerc, M. Lehman, and T. Volkmer. 2020a. Homogenes und kombiniertes Buchen-Brettschichtholz [Homogeneous and combined glued-laminated timber made from beech]. Rep. No. REF-1011-04200. Bern, Switzerland: FOEN.
Ehrhart, T., R. Steiger, M. Lehmann, and A. Frangi. 2020b. “European beech (Fagus sylvatica L.) glued laminated timber: Lamination strength grading, production and mechanical properties.” Eur. J. Wood Prod. 78 (Jun): 971–984. https://doi.org/10.1007/s00107-020-01545-6.
Ehrhart, T., R. Steiger, P. Palma, E. Gehri, and A. Frangi. 2020c. “Glulam columns made of European beech timber: Compressive strength and stiffness parallel to the grain, buckling resistance and adaptation of the effective-length method according to Eurocode 5.” Mater. Struct. 53 (Jul): 91. https://doi.org/10.1617/s11527-020-01524-6.
FOEN (Swiss Federal Office for the Environment). 2019. Jahrbuch Wald und Holz [Yearbook forest and wood]. [In German.] Bern, Switzerland: FOEN.
Frangi, A., R. Steiger, and M. Theiler. 2015. “Design of timber members subjected to axial compression or combined axial compression and bending based on 2nd order theory.” In Proc., Int. Network on Timber Engineering Research (INTER)—Meeting 48, 48-2-2. Karlsruhe, Germany: Timber Scientific Publishing, KIT Holzbau und Baukonstruktion.
Gattas, J. M., M. L. O’Dwyer, M. T. Heitzmann, D. Fernando, and J. G. Teng. 2018. “Folded hybrid FRP-timber sections: Concept, geometric design and experimental behavior.” Thin Walled Struct. 122 (Jan): 182–192. https://doi.org/10.1016/j.tws.2017.10.007.
Glos, P. 1981. “Zur Modellierung des Festigkeitsverhaltens von Bauholz bei Druck-, Zug- und Biegebeanspruchung” [Modelling the strength characteristics of structural timber in compression, tension, and bending]. In Vol. 42 of Berichte zur Zuverlässigkeitstheorie der Bauwerke [Reports on the reliability theory of structures]. [In German.] Munich, Germany: Technische Universität München.
Glos, P., J. K. Denzler, and P. W. Linsenmann. 2004. “Strength and stiffness behaviour of beech laminations for high strength glulam.” In Proc., CIB-W18 Meeting 37, 37-6-3. Karlsruhe, Germany: Lehrstuhl für Ingenieurholzbau und Baukonstruktionen.
Hartig, J. U., J. Wehsener, and P. Haller. 2016. “Experimental and theoretical investigations on moulded wooden tubes made of beech (Fagus sylvatica L.).” Constr. Build. Mater. 126 (Nov): 527–536. https://doi.org/10.1016/j.conbuildmat.2016.09.042.
Heiduschke, A., and P. Haller. 2010. “Fiber-reinforced plastic-confined wood profiles under axial compression.” Struct. Eng. Int. 20 (3): 246–253. https://doi.org/10.2749/101686610792016772.
Hu, Q., Y. Gao, X. Meng, and Y. Diao. 2020. “Axial compression of steel–timber composite column consisting of H-shaped steel and glulam.” Eng. Struct. 216 (Aug): 110561. https://doi.org/10.1016/j.engstruct.2020.110561.
Issa, C. A., and Z. Kmeid. 2005. “Advanced wood engineering: Glulam beams.” Constr. Build. Mater. 19 (2): 99–106. https://doi.org/10.1016/j.conbuildmat.2004.05.013.
Kia, L., and H. R. Valipour. 2021. “Composite timber-steel encased columns subjected to concentric loading.” Eng. Struct. 232 (Apr): 111825. https://doi.org/10.1016/j.engstruct.2020.111825.
Kia, L., and H. R. Valipour. 2022. “Radiata pine and Douglas fir timber steel encased columns subjected to concentric and eccentric loading.” J. Struct. Eng. 148 (2): 04021272. https://doi.org/10.1061/(ASCE)ST.1943-541X.0003266.
Kim, Y., and K. Harries. 2010. “Modeling of timber beams strengthened with various CFRP composites.” Eng. Struct. 32 (10): 3225–3234. https://doi.org/10.1016/j.engstruct.2010.06.011.
Krueger, G. P., and L. B. Sandberg. 1974. “Ultimate-strength design of reinforced timber beams: Evaluation of design parameters.” Wood Sci. 6 (4): 316–330.
Lackner, C., M. Schreck, and A.-M. Walli. 2023. Österreichischer Waldbericht 2023—Wir kümmern uns um den Wald [Austrian forest report 2023—We care for the forest]. [In German.] Vienna, Austria: Federal Ministry Republic of Austria Agriculture, Forestry, Regions and Water Management.
Lantos, G. 1964. “Reinforced and post-tensioned glue-laminated beams under development at TRADA labs.” Civ. Engrg. (London) 59 (690): 86–87.
Lantos, G. 1970. “The flexural behavior of steel reinforced laminated timber beams.” Wood Sci. 2 (3): 136–143.
Lantos, G., and R. Harvey. 1964. Tests on flitch and plank beams. High Wycombe, UK: Timber Research and Development Association.
Mark, R. 1961. “Wood-aluminum beams within and beyond the elastic range. Part I: Rectangular sections.” For. Prod. J. 11 (10): 477–484.
Mark, R., S. F. Adams, and M. Maiti. 1968. “Design of a composite pole laminate.” For. Prod. J. 18 (4): 23–28.
Mayo, J. 2015. Solid wood: Case studies in mass timber architecture, technology and design. London and New York: Routledge.
McKenna, F., M. H. Scott, and G. L. Fenves. 2010. “Nonlinear finite-element analysis software architecture using object composition.” J. Comput. Civ. Eng. 24 (1): 95–107. https://doi.org/10.1061/(ASCE)CP.1943-5487.0000002.
Millar, R. B. 2011. “Maximum likelihood estimation and inference: With examples in R, SAS and ADMB.” In Statistics in practice, 1st ed. New York: Wiley.
Mpidi Bita, H., J. A. J. Huber, P. Palma, and T. Tannert. 2022. “Prevention of disproportionate collapse for multistory mass timber buildings: Review of current practices and recent research.” J. Struct. Eng. 148 (7): 04022079. https://doi.org/10.1061/(ASCE)ST.1943-541X.0003377.
Nabati, A., T. Ghanbari-Ghazijahani, and H. R. Valipour. 2021. “Innovative flitch sandwich beams with steel core under four-point bending.” Eng. Struct. 233 (Apr): 111724. https://doi.org/10.1016/j.engstruct.2020.111724.
Nagaraj, M. 2005. “Experimental and computational investigation of FRP reinforced glulam columns including associated software development.” M.Sc. thesis, Dept. of Civil and Resource Engineering, Dalhousie Univ.
Palma, P., and R. Steiger. 2020. Fibre-reinforced polymers in timber structures: Description and evaluation of possible applications and overview of research and development work carried out until 2020. Dübendorf, Switzerland: Swiss Federal Laboratories for Materials Science and Technology.
Peterson, J. 1965. “Wood beams prestressed with bonded tension elements.” J. Struct. Div. 91 (1): 103–120. https://doi.org/10.1061/JSDEAG.0001199.
Python Software Foundation. 2020. Python (version 3.9). Wilmington, DE: Python Software Foundation.
Raftery, G. M., and A. M. Harte. 2011. “Low-grade glued laminated timber reinforced with FRP plate.” Composites, Part B 42 (4): 724–735. https://doi.org/10.1016/j.compositesb.2011.01.029.
SIA (Swiss Society of Engineers and Architects). 2013. Basis of structural design. SIA 260:2013. Zurich, Switzerland: SIA.
Sliker, A. 1962. “Reinforced wood laminated beams.” For. Prod. J. 12 (12): 91–96.
Soriano, J., B. P. Pellis, and N. T. Mascia. 2016. “Mechanical performance of glued-laminated timber beams symmetrically reinforced with steel bars.” Compos. Struct. 150 (Aug): 200–207. https://doi.org/10.1016/j.compstruct.2016.05.016.
Spaun, F. 1981. “Reinforcement of wood with fiberglass.” For. Prod. J. 31 (4): 26–33.
Sroka, K., P. Palma, R. Steiger, T. Ehrhart, A. Frangi, T. Strahm, and E. Gehri. 2023. “Unreinforced and steel-reinforced columns made of European beech glued-laminated timber.” In Proc., World Conf. on Timber Engineering (WCTE) 2023. New York: Curran Associates.
Steiger, R., E. Serrano, M. Stepinac, V. Rajčić, C. O’Neill, D. McPolin, and R. Widmann. 2015. “Strengthening of timber structures with glued-in rods.” Constr. Build. Mater. 97 (Oct): 90–105. https://doi.org/10.1016/j.conbuildmat.2015.03.097.
Taheri, F., M. Nagaraj, and P. Khosravi. 2009. “Buckling response of glue-laminated columns reinforced with fiber-reinforced plastic sheets.” Compos. Struct. 88 (3): 481–490. https://doi.org/10.1016/j.compstruct.2008.05.013.
Tanaka, H., H. Idota, and T. Ono. 2006. “Evaluation of buckling strength of hybrid timber columns reinforced with steel plates and carbon-fiber sheets.” In Proc., World Conf. on Timber Engineering (WCTE) 2006. New York: Curran Associates.
Theakston, F. 1965. “A feasibility study for strengthening timber beams with fiberglass.” Can. Agric. Eng. 7 (1): 17–19.
Theiler, M. 2014. “Stabilität von Axial auf Druck beanspruchten Bauteilen aus Vollholz und Brettschichtholz” [Stability of solid wood and glued-laminated timber components under axial compression]. [In German.] Ph.D. thesis, Dept. of Civil, Environmental and Geomatic Engineering, ETH Zürich.
Theiler, M., A. Frangi, and R. Steiger. 2013. “Strain-based calculation model for centrically and eccentrically loaded timber columns.” Eng. Struct. 56 (6): 1103–1116. https://doi.org/10.1016/j.engstruct.2013.06.032.
von Tetmajer, L. 1903. Die Gesetze der Knickungs- und der zusammengesetzten Druckfestigkeit der technisch wichtigsten Baustoffe [Laws of buckling and composite compressive strength of the most important structural materials]. [In German.] 3rd ed. Vienna, Austria: Franz Deuticke.
Woschitz, R., and J. Zotter. 2017. “Holzhochhaus Hoho Wien—Das Tragwerkskonzept” [High-rise timber building HoHo Vienna–The structural concept]. [In German.] Österreichische Ingenieur- und Architekten-Zeitschrift 162 (Jun): 1–12.
Xu, F., S. Xuan, W. Li, X. Meng, and Y. Gao. 2022. “Compressive performance of steel-timber composite L-shaped columns under concentric loading.” J. Build. Eng. 48 (May): 103967. https://doi.org/10.1016/j.jobe.2021.103967.
Yang, H., W. Liu, W. Lu, S. Zhu, and Q. Geng. 2016. “Flexural behavior of FRP and steel reinforced glulam beams: Experimental and theoretical evaluation.” Constr. Build. Mater. 106 (Mar): 550–563. https://doi.org/10.1016/j.conbuildmat.2015.12.135.
Žegarac Leskovar, V., and M. Premrov. 2021. “A review of architectural and structural design typologies of multi-storey timber buildings in Europe.” Forests 12 (6): 757. https://doi.org/10.3390/f12060757.
Zhu, M. J., F. McKenna, and M. H. Scott. 2018. “OpenSeesPy: Python library for the OpenSees finite element framework.” SoftwareX 7 (Jun): 6–11. https://doi.org/10.1016/j.softx.2017.10.009.
Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 150 • Issue 2 • February 2024
Copyright
© 2023 American Society of Civil Engineers.
History
Received: Apr 20, 2023
Accepted: Aug 30, 2023
Published online: Dec 5, 2023
Published in print: Feb 1, 2024
Discussion open until: May 5, 2024
ASCE Technical Topics:
- Bars (structure)
- Building materials
- Columns
- Cross sections
- Engineering fundamentals
- Engineering materials (by type)
- Foundation design
- Foundations
- Geotechnical engineering
- Load bearing capacity
- Materials engineering
- Mathematics
- Metals (material)
- Methodology (by type)
- Numerical methods
- Steel
- Steel columns
- Steel structures
- Structural engineering
- Structural members
- Structural steel
- Structural systems
- Structures (by type)
- Wood and wood products
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.