Design of steel-wood-steel connections at the ambient and elevated temperature

Document Type : Research Paper

Authors

Department of Mechanical Engineering, Insituto Politécnico do Porto. ISEP, Instituto Superior de Engenharia do Porto, 4249-015 Porto, Portugal

Abstract

The goal of this work is to study steel-wood-steel (S-W-S) connections in double shear with steel dowels submitted to fire. The design at the ambient temperature was based in Eurocode 5 part 1-1 to determine the number of dowels required based on the connection characteristics. To analyze the influence of these characteristics, connections with dowels diameters with 6, 8, 10 and 12 mm, wood type GL20h, GL24h, GL28h and GL32h and the applied load of 10, 15 and 20 kN were studied. The design at the elevated temperatures was based on the Eurocode 5 part 1-2 and Eurocode 3 part 1-2, to obtain the protection thickness required for fire safety. The protection materials used were the glued laminated timber (Glulam) and type F gypsum plasterboard. The analysis of different parameters and how they influence the connection, was studied clearly using the finite element method. The temperature field allows to determine the char layer in the connections with different wood densities, when unprotected, and compare the protection efficiency with two different types of materials. As conclusion, decreasing the dowels diameter and increasing the applied load, the number of the dowels will increase. With the increasing of the dowel diameters and the wood density, it is possible to observe that the fire capability in the S-W-S connections increases.

Keywords

[1] K. Bell et al., 2008, Handbook 1-Timber Structures, Leonardo da Vinci Pilot Projects: Educational Materials for Designing and Testing of Timber Structures, TEMTIS.
[2] M. Tavakkol-khah, Klingsch W., 1997, Calculation model for predicting fire resistance time of timber members, Fire Safety Science-Proceedings of the Fifth International Symposium, 5: 1201–1211.
[3] Laplanche K, Dhima D, and Racher P., 2006, Thermo-mechanical analysis of the timber connection under fire using 3D finite element model, 9th world conference on timber engineering WCTE, Portland/Oregon, USA, 1: 279–286.
[4] Frangi A, Schleifer V, Fontana M, Hugi E., 2010, Experimental and Numerical Analysis of Gypsum Plasterboards in Fire, Fire Technology, 46: 149–167. https://doi.org/10.1007/s10694-009-0097-5
[5] CEN, EN1995-1-2: Eurocode 5. Design of timber structures. Part 1-2: General Structural fire design. Brussels, 2004.
[6] Cachim PB, Franssen Jean-Marc., 2010, Assessment of Eurocode 5 Charring Rate Calculation Methods, Fire Technology, 46: 169-181. https://doi.org/10.1007/s10694-009-0092-x
[7] Frangi A, Erchinger C, Fontana M., 2010, Experimental fire analysis of steel-to-timber connections using dowels and nails, Fire and Materials: An International Journal, 34(1): 1-19. https://doi.org/10.1002/fam.994
[8] Fonseca EMM, Barreira LMS., 2011, Experimental and Numerical Method for Determining Wood Char-Layer at High Temperatures Due to An Anaerobic Heating, International Journal of Safety and Security Engineering, 1(1): 65–76. Doi: 10.2495/SAFE-V1-N1-65-76
[9] Peng L, Hadjisophocleus G, Mehaffey J, Mohammad M., 2011, Predicting the Fire Resistance of Wood-Steel-Wood Timber Connections, Fire Technology, 47: 1101-1119. https://doi.org/10.1007/s10694-009-0118-4
[10] Peng L, Hadjisophocleus G, Mehaffey J, Mohammad M., 2011, On the Fire Performance of Double-shear Timber Connections, Fire Safety Science - Proceedings of the tenth International Symposium, 1207–1218.
[11] Fonseca EMM, Coelho DCS, Barreira LMS., 2012, Structural safety in wooden beams under thermal and mechanical loading conditions, International Journal of Safety and Security Engineering, 2(3): 242–255. Doi: 10.2495/SAFE-V2-N3-242-255
[12] Norgaard J, Mydin O A., 2013, Drywall Thermal Properties Exposed to High Temperature and Fire Condition, Jurnal Teknologi, 62(1): 63–68.
[13] Fonseca EMM, Ramos HME, Silva HJG, Ferreira DRSM., 2013, Thermal Analysis of Wood-Steel Hybrid Construction, 4th International Conference on Integrity, Reliability and Failure, paper ref:4090.
[14] Loss C, Piazza M, Zandonini R., 2016, Connections for steel–timber hybrid prefabricated buildings, Part II: Innovative modular structures. Construction and Building Materials, 122: 796–808. https://doi.org/10.1016/j.conbuildmat.2015.12.001
[15] Elza MM Fonseca, Pedro AS Leite, Lino Silva, 2020, Wood Connections Under Fire Conditions Protected with Gypsum Plasterboard Types A and F, Chapter No:7, Book: Advances in Fire Safety Engineering. CILASCI 2019. P. A. G. Piloto et al (Eds), Lecture Notes in Civil Engineering, vol 1. Cham, Springer Nature Switzerland, 93-106. https://doi.org/10.1007/978-3-030-36240-9_7
[16] Elza MM Fonseca, Lino Silva, Pedro AS Leite, 2020, Numerical model to predict the effect of wood density in wood–steel–wood connections with and without passive protection under fire, Journal of Fire Sciences 2020, in Special Issue: 5th Iberian-latin-american congress on fire safety, P. A. G. Piloto et al (Eds): CILASCI 2019, 38(2): 122-135. https://doi.org/10.1177/0734904119884706
[17] Martins R, Fonseca EMM., 2018, Fire Behaviour of Protected W-S-W Connections with a Steel Plate as the Central Member and Different Dowels Diameter, International Journal of Science and Technology, 4(3): 60-78. https://dx.doi.org/10.20319/mijst.2018.43.6078
[18] Martins R, Fonseca EMM., 2018, W-S-W Connections with a Steel Plate as the Central Member and Different Dowels Diameter at High Temperature, In: 1st Iberic Conf. on Theoretical and Experimental Mechanics and Materials / 11th National Cong. on Experimental Mechanics, Ed. Gomes. INEGI/FEUP, 239-248.
[19] Fonseca EMM, Silva L, Leite P., 2019, Fire safety of wood-steel connections, In: 4th International Conference on Numerical and Symbolic Computation Developments and Applications – Developments and Applications, Ed. Amélia, Barbosa et al. APMTAC, 109-118.
[20] Débora M. Rodrigues, Alexandre Araújo, Elza M. M. Fonseca, Paulo A. G. Piloto, Jorge Pinto, 2017, Behaviour on Non-Loadbearing Tabique Wall Subjected to Fire – Experimental and Numerical Analysis. Journal of Building Engineering, 9:164-176. https://doi.org/10.1016/j.jobe.2016.11.003
[21] David L. P. Couto, Elza M. M. Fonseca, Paulo A. G. Piloto, Jorge M. Meireles, Luísa M. S. Barreira, Débora R. S. M. Ferreira, 2016, Perforated cellular wooden slabs under fire: numerical and experimental approaches, Journal of Building Engineering, 8:218 - 224. https://doi.org/10.1016/j.jobe.2016.10.007
[22] CEN, EN1194:1999 Timber structures - Glued laminated timber – Strength classes and determination of characteristic values. Brussels, 1999.
[23] CEN, EN1993-1-1: Eurocode 3. Design of steel structures. Part 1-1: General rules and rules for building. Brussels, 2005.
[24] CEN, EN1993-1-2: Eurocode 3. Design of steel structures. Part 1-2: General rules - Structural Fire Design. Brussels, 2005.
[25] Mehaffey JR, Cuerrier P, Carisse G.A., 1994, A Model for Predicting Heat Transfer Through Gypsum Board/Wood-Stud Walls Exposed to Fire, Fire and Materials, 18: 297–305. https://doi.org/10.1002/fam.810180505
[26] CEN, EN1995-1-1: Eurocode 5. Design of timber structures. Part 1-1: General Common rules and rules for buildings. Brussels, 2004.
[27] CEN, EN1991-1-2: Eurocode 1. Action on structures. Part 1-2: General actions - Actions on Structures Exposed to Fire. Brussels, 2002.
[28] Harman KA, Lawson JR., 2007, A Study of Metal Truss Plate Connectors When Exposed to Fire, NISTIR 7393, National Institute of Standards and Technology.
[29] Peng L, Hadjisophocleous G, Mehaffey J, Mohammad M., 2011, On the Fire Performance of Double-shear Timber Connections, Fire Safety Science, 42: 1207-1218. Doi: 10.3801/IAFSS.FSS.10-1207
[30] Jean-Marc Franssen, Paulo Vila Real, 2015, Fire Design of Steel Structures, Published by: ECCS-European Convention for Constructional Steelwork, 2nd Edition.
Volume 52, Issue 1
March 2021
Pages 85-101
  • Receive Date: 21 December 2020
  • Revise Date: 20 January 2021
  • Accept Date: 21 January 2021