Pull-compression tests on glued-in metric thread rods parallel to grain in glulam and laminated veneer lumber of different timber species

Ongoing development of timber and timber
products made from European hardwoods like ash and
beech influences the selection of acceptable methods for
connecting these elements and thus demands validation and
application of current design methods for softwood and
glulam. For the last 20 years, despite many national and
international research projects and practical applications of
glued-in rods in timber structures, there is still no universal
standard with respect to their design. The use of adhesives
available for bonding rods and timber is limited to softwood.
This work shows the performance of different timber
species Norway spruce (Picea abies Karst.), European
ash (Fraxinus excelsior L.) and European beech (Fagus
silvatica L.) and engineered timber products (laminated
veneer lumber made of Norway spruce and European
beech) based on comprehensive pull-compression tests of
glued-in rods. For characterizing the elastic and elasticplastic
behavior, failure loads as well as stiffness and
ductility were considered whereby the rod diameter and
anchorage length were maintained constant. The aim of the
research was to show that glued-in rods cannot only be
used in softwoods and glulam members but also in hardwoods
and in wood-based products such as LVL.