ESTIMATING TENSILE STRENGTH IN PINUS RADIATA STRUCTURAL TIMBER

Altogether, 1862 Pinus radiata D.Don structural boards were tested in tension to examine five selected parameters of tensile strength, and to verify the code-assigned characteristic tensile strength values. Knot area ratio (KAR) alone does not predict tensile strength at the weakest point of the board; local bending stiffness at the failure point EP, fail shows a stronger correlation with tensile strength, and this presents a possibility for non-destructive estimation of tensile strength in P. radiata structural timber. The mean, 5th percentile, and characteristic strength in tension were studied for the test boards and the results indicated that the code values for current visual stress-grading systems of P.radiata need to be revised because the characteristic tensile strengths obtained from the tests were significantly lower than the values assigned in the standards