Abstract
To evaluate the effect of tightening velocity on the torque coefficient of timber jointing with bolts, the tightening tests were carried out for 4 conifers used in wooden buildings under 5 tightening velocities. As a result, it was found that the torque coefficient decreased as the tightening velocity increased. Furthermore, it would appear that the difference in torque coefficients among species also decreases under 20 rpm. In addition, the torque coefficient of timber jointing with bolts had the same properties as joints without timber. Therefore, it seemed that the torque coefficient of bolted timber joints can be considered the same as the torque coefficient of joints without timber. The spread of torque coefficients might diminish when the tightening velocity was set at 20 rpm.
