Properties and grading of Danto and Ramon 2 by 4's
2006
Green, D.W. | Rosales, A.N.
Physical and mechanical properties were obtained for approximately 600 2 by 4's of Ramon (Brosimun alicastrum) and 600 2 by 4's of Danto (Vatairea lundellii), from Guatemala. The lumber was visually graded according to U.S. grading rules. Full-sized tests were conducted in bending and in tension and compression parallel to the grain. Clearwood tests were conducted in bending and shear. Little relationship was found between the flexural properties of 2 by 4's and those of knot-free specimens cut from the lumber. Visual grading rules satisfactorily sorted lumber into grades with distinct strength values. However, modulus of elasticity varied little by visual grades. The relationship between tensile strength and bending strength for both species was similar to that of domestic softwood and hardwood species. The relationship between compression strength and bending strength was similar to domestic species for Ramon, which did not contain interlocked grain, but not for Danto, which contained interlocked grain. The conservative relationship of ASTM D 1990 could be used to estimate the compressive strength of these two species from bending strength. However, it is cautioned that compression-bending relationships assumed in ASTM standard D 6570 for mechanically graded lumber should not be used with either tropical or temperate hardwood species that typically contain interlocked grain without further verification of the inherent relationship.
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