Grain angle and temperature effect on embedding strength

The objective of this research is to evaluate the effect of temperature and grain angles on the wood embedding strength in the range from 20 to 140 °C. To this end, a reduction factor of the wood embedding strength is proposed as a continuous function of the grain angle and the temperature, for use in modeling of timber bolted connections. Embedding tests were carried out with 252 specimens of Eucalyptus grandis, according to ASTM D 5764-97a [35] standard. The embedding strength, reduction factor, glass transition temperature and moisture content were determined. The minimum values of the characteristic embedding strengths, parallel (fh,0,k) and perpendicular (fh,90,k) to the grain, were observed at 60 and 80 °C, respectively. For all grain angles, except 15°, the embedding strength presented the first relative minimum at 60 °C. Based on the experimental results, a continuous function of the reduction factor of the embedding strength was then determined. To predict the load-bearing capacity of bolted joints through numerical models, the reduction factor of the embedding strength from the present paper can be used in future research.