EFFICIENT USE OF RED OAK FOR CLUED-LAMINATED BEAMS

A red oak glued-laminated beam combination was developed to achieve a bending strength of 16.5 MPa (2,400 psi) and a modulus of elasticity o f 12.4 GPa (1.8 x 10(6) psi). Thirty beams of two sizes were evaluated to determine the adequacy of ASTM D 3737 (ASTM, 1992a) procedures for prediction of glued-laminated beam design stress and stiffness, and t o verify the volume effect equation currently in use, Lumber propertie s were recorded prior to beam manufacture for use in the ASTM D 3737 a nalysis. Data were analyzed using both knot data collected for each la mination grade, and for the pooled knot data of combined lamination gr ades to increase knot data sample size. Beam data were normalized to d istinguish the difference in bending strength due to volume effect fro m the difference in bending strength due to lumber properties. Beam st rengths from pooled knot data were not normalized. Bean; rests indicat e that ASTM D 3737 can be used to satisfactorily predict the strength and stiffness of red oak glued-laminated beams, and that the current v olume effect model adequately predicts the behavior of red oak glued-l aminated beams.