Performance of timber connections with single and multiple glued-in threaded steel rods

The experimental research conducted within this thesis project focused on joints composed of softwood glulam members and mild steel glued-in threaded rods. In a first phase, the influence of the embedment length and the rod diameter using three different adhesives was studied to establish performance benchmarks. In the second phase, the investigation focused on the influence of manufacturing defects on the capacity of timber joints with glued-in steel rods. For this purpose, timber joints were manufactured with two different types of defects likely to be encountered during their manufacturing on-site: i) rods placed at an angle to the drill hole instead of being in the joint axis, and ii) rod placed at the edge of the drill hole instead of fully centred. Finally, in the third phase, joints with multiple rods (two, three and four rods) were manufactured and tested. The adhesive type and rod diameter were kept constant and the embedment length and the spacing between rods were varied during this phase. In all phases of this experimental campaign, specimens were tested under uniaxial quasi-static tension loading. The results showed that, for single glued-in rod joints using mild steel threaded rods, a ductile-type of failure can be consistently attained if the embedment length of the rod is long enough (>10d). Furthermore, the results for specimens with bonding defects considered in this study had no significant negative impact on the capacity of the joints if compared to the results obtained in the first experimental phase. Finally, a spacing between rods greater than four times the rod diameter demonstrated to be sufficient to facilitate a ductile steel yielding failure as long as the joints were manufactured with sufficient embedment length (>10d). The results from this study can contribute towards better understanding of the influence that the parameters under investigation have on the performance on timber joints with glued-in rods, as well as to translate this information to promote the development of more studies on further applications such as moment resisting connections.Applied Science, Faculty ofCivil Engineering, Department ofGraduat