Combined loading of angled screws in timber connections A study to evaluate the stiffness and load-carrying capacity of inclined screws
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Structural engineering and building technology (MPSEB), MSc
Publicerad
2023
Författare
KULLANDER, GUSTAV
SANDSTRÖM, ALEXANDER
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Connections have a deciding role in the design of timber structures as they often
present complex solutions and behaviour, which makes them critical areas during
the design process. As wood has orthotropic properties the structural behaviour of
connections becomes highly influenced by fastener- and force orientation. For
connections with inclined screws, this behaviour is not fully reflected on in the current
design standards. Therefore, the aim of this thesis is to study the combined
loading of angled screws in timber-timber connections by evaluating the slip modulus
and load-carrying capacity. The study investigates the behaviour of timber
connections with inclined screws under various load scenarios and screw angles. The
thesis utilizes experimental test results from previous studies, analytical equations
from design standards and previous research, while the numerical part is carried out
through finite element analysis in ABAQUS.
The results of the study indicate that the slip modulus and load-carrying capacity
of timber connections with inclined screws are underestimated by Eurocode 5 in
general but especially when considering certain angles. This does still remain true
with the second generation of Eurocode 5. The research does however demonstrate
that the use of inclined screws can significantly increase the load-carrying capacity
of timber connections, as well as the stiffness and improve their overall performance.
Additional research on how to implement different load-to-grain angles is suggested
to improve the perfomance further.