Preservative treatment of Scots pine and Norway spruce

Tests were carried out to investigate the withdrawal strength and bending moment resistance of screwed T-type, end-to-side grain joints constructed of Turkish beech (Fagus Orientalis L.), European oak (Quercus petraea L.), and scotch pine (Pinus Sylvestris L.). Three different diameters ofsheet metal screws were used. Screw diameters were 5 mm, 6 mm, and 7 mm, but all screw lengths were 70 mm in this study. T-type specimens were subjected to both withdrawal and bending tests. Experimental results indicated that the joints constructed of beech with 7-mm-diameter screws yielded the highest strength in both withdrawal and bending tests, and the joints constructed of scotch pine with 5-mm-diameter screws had the lowest withdrawal strength and bending moment resistance. It was concluded that the general formula that is used to predict the two-pin bending moment resistance of a dowel joint as a function of a single dowel could also be used to predict the moment resistance ofthe same type of screwed joint. In other words, the bending moment resistance ofthe joints could be predicted as a function of ultimate withdrawal strength of a single screw.