Effect of fiberglass reinforcement on the behavior of bolted wood connections

Abstract

Bolted connections often fail by a shear plug or by splitting beneath the bolt caused by tension perpendicular-to-grain stress as the bolt wedges its way through the wood. Preventing this type of failure enhances both the capacity and reliability of bolted connections. This research investigated the use of fiberglass reinforcement to enhance the load-carrying capacity of bolted wood connections. Matched specimens were reinforced with one, two, or three layers of bidirectional fiberglass cloth and configured to ensure a Mode I failure as defined by the yield theory in the National Design Specification. A total of 80 single-bolt, double-shear connections were tested, with 40 loaded parallel-to-grain and 40 perpendicular-to-grain. For parallel-to-grain loading, the reinforcement changed the mode of failure from an abrupt, catastrophic type associated with tension perpendicular-to-grain stress to a ductile type associated with bearing stress. These results are applicable to Mode I failures where surface reinforcement is most effective; smaller increases in strength are expected for thicker main members that experience Modes III and IV failures.

Citation

Soltis, Lawrence A.; Ross, Robert J.; Windorski, Daniel E. 1997. Effect of fiberglass reinforcement on the behavior of bolted wood connections. Journal of contemporary wood engineering. Vol. 8, no. 3 (fall 1997): Pages 19-24