Evolution of tensile design stresses for lumber

Abstract

Until approximately 1965, allowable design stresses for lumber in tension were taken as equal to those assigned for bending. As interest in tensile properties increased, testing machines were designed specifically to stress lumber in tension. Research results that accumulated on tensile tests of full-size lumber suggested lower design stresses for tension than for bending for both machine stress rated and visually graded lumber. The latest change for visual grades, based on a review of research data available up to 1977, was a reduction in design tensile stresses that varied by size and grade.

Keywords

Tension, tensile strength, allowable design stresses, visual grading, machine grading, lumber

Citation

Galligan, William L.; Gerhards, C. C.; Ethington, R. L. 1979. Evolution of tensile design stresses for lumber. Gen. Tech. Rep. FPL-28. Madison, WI: U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 8 p.