Materiales de Construcción, Vol 69, No 335 (2019)

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


https://doi.org/10.3989/mc.2019.00319

J. R. Villar-García
Departamento de Ingeniería del Medio Agronómico y Forestal, Centro Universitario de Plasencia, Universidad de Extremadura, Spain
orcid http://orcid.org/0000-0003-1283-606X

P. Vidal-López
Grupo de Investigación Ingeniería Mecánica y Fluidos, Departamento de Ingeniería del Medio Agronómico y Forestal, Universidad de Extremadura, Spain
orcid http://orcid.org/0000-0002-8941-604X

J. Crespo
Plataforma de Ingeniería de la Madera Estructural, Escuela Politécnica Superior, Universidad de Santiago de Compostela, Spain
orcid http://orcid.org/0000-0003-1517-4030

M. Guaita
Plataforma de Ingeniería de la Madera Estructural, Departamento de Ingeniería Agroforestal, Universidad de Santiago de Compostela, Spain
orcid http://orcid.org/0000-0001-9159-7348

Abstract


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 cross-sections 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.

Keywords


Wood; Method of finite elements; Modelization; Mechanical properties; Deformation

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References


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