How moisture timing affects steel connectors in wood construction
A new study reveals that when wood dries after steel dowels are installed, connection stiffness can jump 50%, transforming how builders should sequence assembly and environmental conditioning. The finding matters for engineers designing cost-effective timber structures and manufacturers planning production workflows in variable humidity climates.
Originaltitel: Moisture and Assembly History Effects on Embedment Properties of Steel Dowels in Spruce and Birch Loaded in Grain Direction
<p>Embedment strength and stiffness of steel dowels in spruce and birch solid wood were investigated in an experimental study, taking into account the moisture and connection assembly history. Thus, in addition to the effect of different mechanical properties of wood at different moisture contents, the effect of changes in the moisture content between the steps of: drilling the dowel hole, assembly of the dowel, and testing of the specimen on the embedment strength and stiffness was studied. Full-hole embedment tests with 12 mm steel dowels showed a decrease in embedment strength with increasing wood moisture content, while the elastic embedment stiffness was not influenced. Drying the wood specimens after the dowel was inserted yielded up to 50% higher elastic embedment stiffness compared with connections drilled and assembled when the equilibrium moisture content was reached. Application of an artificial crack showed only a moderate effect on embedment strength and stiffness, while the ductile embedment behavior was maintained.</p>