Enduring performance of self-tapping screw connection in wood members and WPC members

This study examined the creep performance of self-tapping screw connection in wood members and wood-plastic composite (WPC) members that had been subjected to changes in moisture and stress levels. It was found that the self-tapping screw’s joint strength depended on interlocking and friction force between wood and screw threads, between WPC and screw threads. The pine (Pinus spp.) and the WPC had almost the same creep properties. In wet condition, the pine’s creep was higher than the WPC’s. Burgers mode was able to precisely simulate the short-term creep performance of screw connection in the pine members and in the WPC members. In the wet condition, the creep was apparently higher than that in dry condition. Temperature and relative humidity were two important factors that influenced creep. The higher stress level was, the larger amount of creep would be. Creep rate was the largest in both wet condition and high stress level. It is recommended that the maximum tensile stress level should be limited to 40 % for screw connection in the wood members and the WPC members.

Flexural behavior of osb reinforced wood truss

In this paper, oriented strand board (OSB) on both sides of the wood truss was used to strengthen the wood truss. The flexural behavior of the reinforced wood truss was studied. The results showed that OSB was an effective technical member to improve the flexural bearing capacity of wood truss. Besides, wood truss and OSB can be firmly combined by using glue bonding and screw connections. The screws served only to apply pressure to the glued joint. And the reinforced wood trusses had good synergy and overall stability. The initial bending stiffness and ultimate bending load of the reinforced wood trusses were increased by 203.20% and 234.39% respectively. Ultimate bending load and initial bending stiffness were improved a little by making the wood truss wider. Compared with the traditional wood truss, the reinforced wood truss had the advantages of simple connection mode, less wood consumption, no rolling machine and easy fabrication.