Comparison of nail-holding performance of Pinus massoniana and Cunninghamia lanceolata dimension lumber based on round steel nails

Abstract

In this study, the influence of the diameter of round steel nails, the guiding bores, and the wood sections on the nail holding performance of Pinus massoniana and Cunninghamia lanceolata dimension lumber was explored. The results showed that the nail-holding power of round steel nails mainly came from their friction with wood fibers, while the radial and tangential sections were also affected by the shearing action of wood fibers. The tangential section reached the largest nail-holding power, followed by the radial section and cross section. Greater wood density was associated with higher nail holding power. Under a large nail diameter, however, high-density wood was prone to plastic cracking, which influenced the nail holding power greatly. Prefabricated guiding bores could prevent plastic cracking in wood to some extent and improve the nail holding power of Pinus massoniana and Cunninghamia lanceolata dimension lumber when diameter of round steel nails was more than 3.0 mm. For Cunninghamia lanceolata characterized by low density and rigidity, the wood fiber was in close contact with the round steel nail and internal cracking could not be easily generated under a large diameter of round steel nails.

Effects of Dowel Rotation Welding Conditions on Connection Performance for Chinese Fir Dimension Lumbers

“…In unwelded wood, the stressstrain curve initially ascended to a peak, subsequently experiencing a precipitous decline, followed by fluctuations with a progressively diminishing amplitude. This behavior is attributed to the frictional forces between the wood fibers, reminiscent of those observed in connections made with round steel nails [4,11,20]. The rapid decline in the curve is attributed to the maximum static friction force prior to dowel extraction, where the primary tensile resistance originates from this maximal static friction (reaching the limit strength at the peak of static friction).…”

“…The radial-cut surface, with its fiber alignment parallel to the welding pressure, facilitates tighter fiber entwining and interlocking, which accounts for its superior tensile strength over the tangential-cut surface. Variations in earlywood and latewood, arrangement patterns, lignin content, and microfibril orientation in radial and tangential cuts also contribute to differences in tensile strength [4,11,[28][29][30][31].…”

“…Because of its excellent insulation, environmental protection, energy saving, and safety, wood structure buildings have been widely recognized and promoted around the world. As a country rich in forestry resources, Chinese fir has been widely used in the furniture and construction industries due to its lightweight and easy processing [1][2][3][4][5][6][7]. Especially in the Guizhou Province, Chinese fir is not only the main economic forest species but is also the main building material of traditional wooden dwellings with national characteristics [8][9][10].…”