Effect of Low Temperature on Embedment Properties in Timber

Embedment properties govern the mechanical performance of dowelled timber joints. Due to widespread applications of timber structures in low-temperature environments, it is necessary to evaluate the embedment properties in timber at low temperature below 0°C. In this study, the embedment tests for steel dowels with 12-mm diameter in glued laminated timber at load-to-grain angles of 0°, 30°, 45°, 60°, and 90° were carried out at 20°C and − 40 ° C using half-hole test configuration. Before being frozen, timber specimens were conditioned in the climatic chamber with a temperature of 20°C and relative humidity of 65% and 85% to reach the equilibrium moisture contents of about 12% and 20%, respectively. For the specimens with moisture content of 12%, the percentage increase in embedment strength was around 0.5%–0.7% per 1°C decrease in temperature. For the specimens with moisture content of 20%, the percentage increase in embedment strength was around 0.5%–1.0% per 1°C decrease in temperature. For the specimens at − 40 ° C , the percentage decrease in embedment strength was around 4%–9% per 1% increase in moisture content. For the specimens at 20°C, the percentage decrease in embedment strength was around 6%–9% per 1% increase in moisture content.