2016 年 65 巻 5 号 p. 354-358
The aim of this study was to evaluate the structural performance of nail joints subjected to different moisture contents (MC). In this study, the nail withdrawal and the single shear tests were conducted. The nails were inserted into sugi and larch specimens in the parallel or perpendicular to the grain directions before MC control. As a result, the nail withdrawal resistance increased with decreasing MC when MC was lower than 30%, and did not exhibit the similar trend when MC was higher than 30%. The nail withdrawal energy per unit length of sugi specimens decreased with increasing MC when MC was lower than 30%, and did not show such a trend when MC was higher than 30%. However, larch specimens did not show the tendency as sugi ones. The yield strength of single shear tests slightly increased as MC decreased in the parallel to the grain direction, but did not show the similar trend in the perpendicular to the grain direction. The correlation between initial stiffness and MC was found to be poor in both parallel and perpendicular to the grain directions.