Lateral resistance of bolted wood-to-concrete connections loaded parallel or perpendicular to grain

Tests were carried out to determine the lateral resistance of bolted lumber-to-concrete connections. Specimens were made of hemlock–fir and spruce–pine–fir lumber and bolted to concrete blocks using anchor bolts. Three sizes of anchor bolts were used, with nominal diameters of 12.7 mm (1/2 in.), 15.8 mm (5/8 in.), and 19.1 mm (3/4 in.). The minimum strength of the connections loaded parallel to grain with a single bolt exceeds the characteristic strength specified in the 1994 edition of the Canadian Standards Association (CSA) standard O86.1 by a factor of 1.6 for 12.7 mm (1/2 in.) diameter bolts and 2.0 for 19.1 mm (3/4 in.) diameter bolts. Results on connections loaded perpendicular to grain showed that the 5th percentile strength of a connection with a single bolt was greater than the characteristic strength specified in the CSA standard by a factor of 1.4–2.5. The reasons for this underestimation of the strength values in the standard are attributed to a low estimate of the embedment strengths of wood and concrete, a low estimate of the yield strength of the bolts, and the lack of a design method that accounts for the axial tensioning effect. Changes to the CSA standard O86.1 provisions were proposed and have been accepted to improve the strength predictions of bolted wood-to-concrete connections. The 2001 edition of standard O86.1 reflects those changes.Key words: wood, anchor bolts, concrete, strength, parallel to grain, perpendicular-to-grain embedment, connections.