THE IMPACTS OF SCREW TIP, INCLINATION ANGLES AND NUMBER OF PENETRATION LAYERS ON SCREW WITHDRAWAL CAPACITY IN AUSTRALIAN MACHINE GRADED PINE

Paper in proceeding, 2023

Connections play an important role in timber structures as they govern the overall stiffness, load-carrying capacity, and most of the ductility in a timber structure. Due to the high axial load-carrying capacity and ease of installation, self-tapping screws are nowadays one of the most widely used fasteners in timber construction. However, variations in national standards, regulations, or even timber species might lead to incorrect predictions for the screw's load-carrying capacity. The current Australian Timber Standard AS 1720.1-2010 has some fundamental limitations since it was primarily derived from old North American research and supplemented in the 1970s with empirical data on Australian hardwoods and a few softwoods. Modern European fasteners are increasingly employed in the Australian building industry, making it critical to examine their performance consistency in the context of Australian timber products. This research work, therefore, aimed to a) evaluate the interactions of numbers of penetration layers, screw tip, and screw characteristic withdrawal strength, b) evaluate the influence of inclination angles on characteristic withdrawal strength, and c) compare experimental results with existing models and provide recommendations.