Truss plate reinforced bolted connections in parallel strand lumber

Abstract

This paper summarizes the results of an investigation into the behaviour of truss plate reinforced single and multiple bolted connections in parallel strand lumber (PSL) under static tension loading. Sixty single-bolt connections were tested with bolt and PSL size combinations of 12.7 mm bolts in 38×140 mm specimens, 15.9 mm bolts in 89×140 mm specimens, and 22.2 mm bolts in 133×191 mm specimens. Another sixty multiple-bolt specimens were tested, using the above-mentioned PSL size and bolt combinations. The multiple-bolt connections consisted of two rows of five bolts in the 38×140 mm and 89×140 mm specimens and two rows of two bolts in the 133×191 mm specimens. Each connection was configured according to the Canadian Standard for Engineering Design in Wood (CAN/CSA 086.1-94) in terms of bolt spacing, edge distances, and end distances. All reinforced single-bolt connections had average ultimate strength increases, compared to unreinforced connections, of 3% for the 133×191 mm, 12% for the 89×140 mm, and 37% for the 38×140 mm specimens. Reinforcement had little effect on the strength of multiple-bolt connections in both the 38×140 mm specimens and the 89×140 mm specimens. The reinforced four-bolt connections in the 133×191 mm specimens had a 7% increase in average ultimate strength. Reinforcement significantly improved the ductility in all the connections tested. Key words: timber connections, parallel strand lumber, multiple bolts, reinforcement, truss plates, ductility, composite wood products, testing, experimental, composite structural lumber.