Abstract
The raising stock of hardwood and the increasing popularity to build with timber are strong drivers to use hardwood as structural material on a regular basis. Despite its outstanding mechanical properties, economic boundary conditions in producing structural hardwood products consequence, however, rather a niche application. Efficient fastener and joint solutions which are optimised for hardwood are one possible solution to increase the share of hardwood in structural applications. Within this contribution a new, innovative and for hardwood optimised screw is benchmarked with a commercial screw. The influence of wood anatomy, thread-grain angle and predrilling on the withdrawal strength of single screws are analysed. For groups of screws, the minimum edge-distance and spacing perpendicular to the grain are determined and various possibilities for end-grain joints investigated. A generic approach for predicting the withdrawal strength of axially loaded self-tapping screws inserted in structural timber or glued laminated timber products from either soft- or hardwood is presented. Models to account for the influence of density, thread-grain angle and predrilling are proposed and regulations for the geometric requirements and execution of groups of screws in end-grain joints discussed.
Original language | English |
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Pages (from-to) | 254-268 |
Number of pages | 15 |
Journal | Wood Material Science and Engineering |
Volume | 14 |
Issue number | 5 |
DOIs | |
Publication status | Published - 3 Sept 2019 |
Keywords
- Axially loaded self-tapping screws
- end-grain joints
- predrilling
- soft- and hardwood
- thread-grain angle
- wood anatomy
ASJC Scopus subject areas
- General Materials Science
Fields of Expertise
- Sustainable Systems