Analysis of the stress state at the double-step joint in heavy timber structures

  1. J. R. Villar-García
  2. P. Vidal-López
  3. J. Crespo
  4. M. Guaita
Revista:
Materiales de construcción

ISSN: 0465-2746

Ano de publicación: 2019

Volume: 69

Número: 335

Tipo: Artigo

DOI: 10.3989/MC.2019.00319 DIALNET GOOGLE SCHOLAR lock_openAcceso aberto editor

Outras publicacións en: Materiales de construcción

Resumo

The double-step joint is among the most frequently used layouts, within carpentry joints, for transmitting higher forces that would allow a single notch. They are especially effective in heavy timber structures. Nowadays, computer-aided manufacturing is being used more often, demanding further progress in its understanding. The conventional design of these joints is conducted by using simplifying assumptions, in particular regarding the shear stress distribution. This is overcome by the use of strength reduction coefficient, which is currently under study. Numerical simulation and experimental tests were carried out with heavy timber crosssections for rafter to tie-beam truss joint. They were manufactured in glue-laminated timber owing to the large cross-sections tested. Experimental load-strain and load-displacement diagrams were compared with numerical results. This allowed observing the great shear stress concentration produced in the failure by shear crack, which suggests the application of conservative shear strength reduction coefficients.

Información de financiamento

The Spanish Government supported this work, research project: AGL2012-39368-C03-01, National R+D+I Plan of the Ministry of Science and Innovation. The authors are grateful to Besteiro Timber Factory for the glulam timber supplied.

Referencias bibliográficas

  • Villar, J.R.; Vidal, P.; Fernández, M.S.; Guaita, M. (2016) Genetic algorithm optimisation of heavy timber trusses with dowel joints according to Eurocode 5. Biosyst Eng. 144, 115-132. https://doi.org/10.1016/j.biosystemseng.2016.02.011
  • Parisi, M.A.; Piazza, M. (2000) Mechanics of plain and retrofitted traditional timber connections. J. Struct. Eng. 126, 1395-1404. https://doi.org/10.1061/(ASCE)0733-9445(2000)126:12(1395)
  • Villar, J.R.; Guaita, M.; Vidal, P.; Arriaga, F. (2007) Analysis of the Stress State at the Cogging Joint in Timber Structures. Biosyst Eng. 96, 79-90. https://doi.org/10.1016/j.biosystemseng.2006.09.009
  • Villar, J.R.; Guaita, M.; Vidal, P.; Argüelles, R. (2008) Numerical simulation of framed joints in sawn-timber roof trusses. Spanish J. Agric. Res. 6, 508-520. https://doi.org/10.5424/sjar/2008064-345
  • Villar-García, J.R.; Crespo, J.; Moya, M.; Guaita, M. (2018) Experimental and numerical studies of the stress state at the reverse step joint in heavy timber trusses. Mater Struct. 51:17. https://doi.org/10.1617/s11527-018-1144-9
  • Feio, A.O.; Lourenço, P.B.; Machado, J.S. (2014) Testing and modeling of a traditional timber mortise and tenon joint. Mater Struct. 47, 213-225. https://doi.org/10.1617/s11527-013-0056-y
  • Parisi, M.A.; Cordié, C. (2010) Mechanical behaviour of double-step timber joints. Constr. Build. Mater. 24, 1364-1371. https://doi.org/10.1016/j.conbuildmat.2010.01.001
  • Branco, J.M.; Piazza, M.; Cruz, P.J.S. (2011) Experimental evaluation of different strengthening techniques of traditional timber connections. Eng. Struct. 33, 2259-2270. https://doi.org/10.1016/j.engstruct.2011.04.002
  • Palma, P.; Cruz, H. (2007) Mechanical behaviour of traditional timber carpentry joints in service conditions-results of monotonic tests. Proc. 16th Int. Conf. From Mater. to Struct. - Mech. Behav. Fail. Timber Struct. ICOMOS Int. Wood Comm.
  • Palma, P.; Ferreira, J.; Cruz, H. (2010) Monotonic tests of structural carpentry joints. World Conf. Timber Eng. (2010).
  • Verbist, M.; Branco, J.M.; Poletti, E.; Descamps, T; Lourenço, PB. (2017) Single Step Joint: overview of European standardized approaches and experimentations. Mater Struct. 50, 161. https://doi.org/10.1617/s11527-017-1028-4
  • CEN EN 1995-1-1:2016. Eurocode 5 : Design of timber structures - Part. 1.1 General. Common rules and rules for buildings.
  • CTE-DB-SE-M 2009 Spanish Technical Building Code, Structural Security, Timber Structures.
  • NEN NEN-EN 1995-1-1+C1+A1:2011/NB:2013nl. National Annex to NEN-EN 1995-1-1+C1+A1 Eurocode 5: Design of timber structures - Part 1-1: General - Common rules and rules for buildings.
  • SIA 265:2012. Timber Structures. Swiss Society of Engineers And Architects.
  • Argüelles Álvarez, R.; Arriaga, F.; Esteban, M.; Íñiguez, G.; Argüelles Bustillo, R. (2015) Estructuras de Madera. Uniones (Timber Structures. Joints), AITIM. Asociación de Investigación Técnica de las Industrias de la Madera y Corcho. Madrid.
  • Aira, J.R.; Íñiguez-González, G.; Guaita, M.; Arriaga, F. (2016) Load carrying capacity of halved and tabled tenoned timber scarf joint. Mater Struct. 49, 5343-5355. https://doi.org/10.1617/s11527-016-0864-y
  • CEN EN 14080:2013. Timber structures. Glued laminated timber and glued solid timber. Requirements.
  • Argüelles Álvarez, R. (1992) Fundamentos de elasticidad y su programación por elementos finitos, (Fundamentals of elasticity and finite element programming), Bellisco. Madrid, (1992).
  • Ortiz Berrocal, L. (2007) Resistencia de Materiales (Strength of Materials), 3rd ed, MCGRAW-HILL, Madrid.
  • CEN EN 408:2011+A1:2012. Timber structures - Structural timber and glued laminated timber - Determination of some physical and mechanical properties.
  • Koch, H.; Eisenhut, L.; Seim, W. (2013) Multi-mode failure of form-fitting timber connections - Experimental and numerical studies on the tapered tenon joint. Eng. Struct. 48, 727-738. https://doi.org/10.1016/j.engstruct.2012.12.002
  • Baño, V.; Argüelles-Bustillo, R.; Regueira, R.; Guaita, M. (2012) Determination of the stress-strain curve in specimens of Scots pine for numerical simulation of defect free beams. Mater. Constr. 62 [306], 269-284. https://doi.org/10.3989/mc.2012.64110
  • Sangree, R.H.; Schafer, B.W. (2009) Experimental and numerical analysis of a halved and tabled traditional timber scarf joint. Constr. Build. Mater. 23, 615-624. https://doi.org/10.1016/j.conbuildmat.2008.01.015
  • Soilán, A.; Arriaga, F.; Baño, V.; Crespo, J.; Guaita, M. (2011) Analysis of the behaviour of the dovetail connection by numerical simulation with the finite element method. In: Joao Negrao y Alfredo G. Dias, editor. Proceeding 1er Ibero-Latin Am. Congr. wood Constr. CIMAD 11., Coimbra, Portugal.
  • Aira, J.R. (2013) Análisis experimental y por el método de los elementos finitos del estado de tensiones en uniones carpinteras de empalme de llave. PhD thesis, Universidad Politécnica de Madrid.
  • ANSYS Inc. ANSYS® (2012) Academic Research, Release 14.0: Help System: ANSYS Mechanical APDL theory reference.
  • Tsai, S.W.; Wu, E.M. (1971) A General Theory of Strength for Anisotropic Materials. J. Compos. Mater. 5, 58-80. https://doi.org/10.1177/002199837100500106
  • Guindos, P. (2011) Three Dimensional Finite Element Models to Simulate the Behaviour of Wood with Presence of Knots, Appling The Flow-Grain Analogy and Validation with Close Range Photogrammetry. PhD thesis, University of Santiago de Compostela.
  • Goldenblat, I.I.; Kopnov, V.A. (1965) Strength of glass reinforced plastics in the complex stress state. Polym. Mech. 1, 54-59. https://doi.org/10.1007/BF00860685
  • Cabrero, J.M.; Gebremedhin, K.G.; Elorza, J. (2009) Evaluation of Failure Criteria in Wood Members. ASABE Annu. Int. Meet., American Society of Agricultural and Biological Engineers. ASABE. Reno, Nevada, EE.UU. (2009).
  • Eberhardsteiner, J. (2002) Mechanisches Verhalten von Fichtenholz. Vienna: Springer Vienna. https://doi.org/10.1007/978-3-7091-6111-1
  • Schmidt, J.; Kaliske, M. (2008) Models for numerical failure analysis of wooden structures. Eng. Struct. 31, 571-579. https://doi.org/10.1016/j.engstruct.2008.11.001
  • Dahl, K.B. (2009) Mechanical properties of clear wood from Norway spruce. PhD thesis, Norwegian University of Science and Technology.
  • Resch, E.; Schmidt, J.; Gereke, T.; Kaliske, M. (2004) GröBe und Einfluss der Streuung der elastischen Eigenschaften von Fichtenholz. (Size and influence of the dispersion of the elastic properties of spruce). LACER. 9, 417-432.
  • Bucur, V. (2006) Acoustics of wood. 2nd ed., Springer- Verlag Berlin Heidelberg, (2006). https://doi.org/10.1007/3-540-30594-7 PMCid:PMC1995072
  • Majano-Majano, A.; Fernández-Cabo, J.L.; Hoheisel, S.; Klein, M. (2012) A Test Method for Characterizing Clear Wood Using a Single Specimen. Exp. Mech. 52, 1079-1096. https://doi.org/10.1007/s11340-011-9560-6
  • Vázquez, C.; Gonçalves, R.; Bertoldo, C.; Baño, V.; Vega, A.; Crespo, J. (2015) Determination of the mechanical properties of Castanea sativa Mill. using ultrasonic wave propagation and comparison with static compression and bending methods. Wood Sci. Technol. 49, 607-622. https://doi.org/10.1007/s00226-015-0719-7
  • Gonçalves, R.; Trinca, A.J.; Cerri, D.G.P. (2011) Comparison of elastic constants of wood determined by ultrasonic wave propagation and static compression testing. Wood Fiber Sci. 43, 64-75.
  • Conde-García, M.; Fernández-Golfín Seco, J.I.; Hermoso Prieto, E. (2007) Improving the prediction of strength and rigidity of structural timber by combining ultrasound techniques with visual grading parameters. Mater. Constr. 57 [288], 49-59. https://doi.org/10.3989/mc.2007.v57.i288.64
  • UNE 56543, Características físico-mecánicas de la madera. Determinación del esfuerzo cortante (Physical-Mechanical Properties of Wood. Determination of the Shear Strength).
  • ASTM D143:14 Standard test methods for small clear specimens of timber. ASTM International, West Conshohocken, PA
  • Aira, J.R.; Arriaga, F.; Íñiguez-González, G.; Crespo, J. (2014) Static and kinetic friction coefficients of Scots pine (Pinus sylvestris L.), parallel and perpendicular to grain direction, Mater. Constr. 64 [315], e030. https://doi.org/10.3989/mc.2014.03913
  • Crespo, J.; Regueira, R.; Soilán, A.; Díez, M.R.; Guaita, M. (2011) Methodology to determine the coefficients of both static and dynamic friction apply to different species of wood. In: Joao Negrao y Alfredo G. Dias, editor. Proceeding 1er Ibero-Latin Am. Congr. wood Constr. CIMAD 11, Coimbra, Portugal.
  • Smith, I.; Landis, E.; Gong, M. (2003) Fracture and Fatigue in Wood, Wiley, Chichester, (2003).
  • DIN EN 1995-1-1/NA:2013. Nationaler Anhang. National festgelegte parameter. Eurocode 5: Bemessung und konstruktion von reglen für den hochbau. (National Annex. Nationally determined parameters. Eurocode 5 : Design of timber structures Common rules and rules for buildings).
  • Bocquet, J.F. (2015) Traditional structural assemblies in the future regulatory context. Eurocode 5: design and calculation of wooden structures. Formation ENSTIB. National School of Wood Science and Timber Engineering - University of Lorraine, Nancy, Lorraine, (2015).
  • Aira, J.R.; Arriaga, F.; Íñiguez-González, G. (2014) Determination of the elastic constants of Scots pine (Pinus sylvestris L.) wood by means of compression tests. Biosyst Eng. 126, 12-22. https://doi.org/10.1016/j.biosystemseng.2014.07.008
  • Colling, F. (2008) Holzbau, Vieweg+Teubner, Wiesbaden, (2008). doi:10.1007/978-3-8348-9551-6. https://doi.org/10.1007/978-3-8348-9551-6 PMCid:PMC3556514
  • Aira, J.R.; Descamps, T.; Van Parys, L.; Léoskool, L. (2015) Study of stress distribution and stress concentration National School of Wood Science and Timber Engineering - University of Lorraine, Nancy, Lorraine, (2015). https://doi.org/10.1007/s00107-015-0891-3