A general procedure for the evaluation of the mechanical properties of structural joints, named
“component method”, is now available from intensive research works at the European
level. This procedure allows the analytical prediction of the resistance, but also of the stiffness
and the deformation capacity, of structural joints under external forces (axial or shear
forces, bending moments …).
The component method is nowadays integrated as a reference procedure in two European design
codes, respectively for steel structures (EC3 [EN1993]) and steel-concrete composite
structures (EC4 [EN1994]). However, its potential scope is much larger and present studies
are aimed to apply to situations as joints in fire, joints under seismic loading, joints under
exceptional loads (Robustness Project) ….
More recently, a research project [CTI-2004] has succeeded in applying the component
method to the investigation of the elastic behaviour of mechanical joints in timber construction.
That is the result of the collaboration of CTIB-TCHN (Belgian Institute for Wood
Technology) and University of Liège.
The main principle of the component method is the following:
• identification of constitutive components subjected to tension, compression or shear in
• determination of the mechanical behaviour of these individual components;
• "assembling" components so as to derive the mechanical properties of the whole joint.
In the present paper, timber joints with dowel fasteners are considered. Two components
may be identified:
• "dowel" component (dowel fastener in bending and shear);
• embedding component (timber member in embedding).
The "dowel" component is known from past researches, whereas little information is available
for the embedding component. EC5 [EN1995] proposes formulation to predict the behaviour
for joints composed of these two components; but it only depends on two factors: the dowel
diameter and the timber density. The influence probably significant of the grain direction
(material strongly anisotropy) and the thickness of the connected members are for instance
Experimental, numerical and analytical investigations have recently been performed by University
of Liège in collaboration with CTIB-TCHN so as to propose another formulation more
precise for joints. Experimental results, performed by CTIB-TCHN, have been used as reference
for the development of numerical model and, then, analytical model. The application of
the component method to the prediction of the elastic behaviour of timber joints consist of
• "local" investigation on components that is to develop analytical models for the prediction
of the elastic behaviour of components;
• "global" investigation on joints that is to develop analytical models for the prediction
of the elastic behaviour of joints.
The application of the component method to timber joints with dowel fasteners is a first step
towards the use of this concept in future to others mechanical joints (screw, punched metal
plate, nail, bolt …). In this case, others components may be derived to cover the field of application