Mechanical performance of poplar laminated veneer lumber truss joints

Poplar laminated veneer lumber (LVL) offers many advantages such as high strength and small variability. This study explored the application of poplar LVL for making light timber trusses in China. A total of 12 poplar LVL truss joint specimens were designed and constructed, including truss support joints and ridge joints connected by bolts and tooth plates. The mechanical properties of the poplar LVL truss joints were experimentally tested and theoretically calculated. It was found that (1) the average bearing capacity of 10-mm bolted joints was 12.98%–22.62% higher than that of 8- or 12-mm bolted ones; (2) the average bearing capacity of ridge joints with 133 mm × 75 mm tooth plates was 23.03% and 28.22% higher than those with 152 mm × 75 mm and 152 mm × 50 mm tooth-plate connected ones; (3) the average bearing capacity of the bolted joints was higher than that of the tooth-plate connected ones when the shape of both joints were the same; (4) The damage of LVL dowel grooves and pull-out of tooth-plates from LVL were observed in the bolted and tooth-plate connected joints, respectively; and (5) The calculated values were, in comparation with the experimental results, were conservative for bolted joints and were in good agreement with the tooth-plate connected ones.