Dowel deformations in multi-dowel LVL-connections under moment loading

Abstract

The aim of the experimental study presented herein is the assessment and quantification of the behavior of individual dowels in multi-dowel connections loaded by a bending moment. For this purpose, doubleshear, steel-to-timber connections with nine steel dowels arranged in different patterns and with different dowel diameters were tested in 4-point bending. In order to achieve a ductile behavior with up to 7° relative rotation, the connections were partly reinforced with self-tapping screws. The reinforcement did not influence the global load-deformation behavior, neither for dowel diameters of 12 mm nor for 20 mm, as long as cracking was not decisive. The deformation of the individual dowels was studied by means of a non-contact deformation measurement system. Thus, the crushing deformation, i.e. the deformation at the steel plate, and the bending deformation of the dowels could be quantified. In case of 12 mm dowels, the bending deformation was larger than the crushing deformation, while it was smaller in case of 20 mm dowels. Moreover, dowels loaded parallel to the grain showed larger bending deformations than dowels loaded perpendicular to the grain. This indicates that the loading of the individual dowels in the connection differs, depending on their location.

Experimental assessment and damage modelling of hybrid timber beam-to-steel column connections under cyclic loads

“…On the other hand, van Beerschoten et al [57] used DIC to measure timber Poisson's ratios and compare these values against the theoretical estimations. Other recent studies that employ DIC in timber specimens can also be found [4,67,68].…”

Constrained displacement boundary condition in embedment testing of dowel‐type fasteners in LVL

“…The use of optical deformation measurement systems, based on digital image correlation (DIC) technique in connection testing, has proven to give insight into the displacement behaviour of the steel dowels as well as into the deformation behaviour of the wood below the dowels . Recently, the combination of optical surface deformation measurement with microcomputed X‐ray tomography gave unprecedented insight into the local deformation behaviour of the porous wood microstructure under embedment loading .…”

“…From a practical, timber engineering point of view, constrained displacement loading of dowels is given in multiple steel‐to‐timber dowel joints loaded by an in‐plane bending moment (cf. Bader et al).…”