Axial Glued-in Steel Timber Joints - Experimental and Numerical Analysis

This paper reports the results of an investigation on the behaviour of axially loaded joints utilising glued-in steel rods. A finite element model has been set up, in order to study the most influencing parameters for the shear stress distribution. Then, a series of tests have been carried out on joints made with Norway Spruce blocks and threaded steel bars, with different epoxy resin formulations and various ratios of hole/bar diameters. Different bar diameters have been used in experimental survey, ranging from 8 to 12 mm. Clearances of 1 or 2 millimetres have been left between bar and hole wall. The reported results are based on a sample of 240 specimens, which can be considered sufficient for statistical reliability. A statistical analysis has been performed, which confirms that: 1) the system proved to be highly efficient and reliable, both with regard to failure load and to joint stiffness; 2) with the epoxy-based adhesive used, the most important parameters affecting the strength and the stiffness of these joints seem to be the thickness of glue line and the viscosity property of the adhesive during the pouring phase; 3) these kinds of joints can be designed as ductile for specific purposes, choosing a suitable diameter of the bar.