Testing of Finger-Joints in Structural Timber for Quality Control

Summary

The ability of different tests to reveal the reduction of strength in finger-jointed timber due to an imperfect glueline was investigated.

Test specimens of different sizes were used and bending and tension loading were applied. The result shows that the standard bending test, though comparatively insensitive to imperfections at the edge-side of the timber, is acceptable provided the grade strength value, increased by a factor larger than unit, is introduced as target value for the strength of the test specimens. However, the results indicate that small specimens, cut from the timber at the joint and tested individually or together in bending or tension, make satisfactory substitutes for full-sized specimens in running control.