MECHANICAL-PROPERTIES OF COMPOSITE LAMINA TED WOOD COMPOSED OF Z-S TREATED STEEL AND SUGI (CRYPTOMERIA-JAPONICA) WOOD

To reinforce sugi (Cryptomeria japonica D. Don) wood and to ascertain the effect of the equivalent section method on Z-S treated steel and w ood composites, three-meter long seven-ply composite laminated woods u sed five sugi laminae with 20 mm thicknesses, and two Z-S treated stee l plates with 2.3 mm or 3.2 mm thicknesses as well as five-ply laminat ed woods made of sugi laminae were produced, and their mechanical prop erties were measured. As adhesive, aqueous vinyl polymer solution-isoc yanate resin (API) was used. The steel plates were adhered without was hing and sanding. The measured MOE (modulus of elasticity) values were compared with the estimated ones using the equivalent section method. Measured MOEs agreed excellently with estimated values. The variation s of the MOE and MOR (modulus of rupture) values of the composite lami nated woods were smaller than those of the laminated woods made of sug i laminae. The average MOE values of the composite laminated moods wit h 2.3 mm and 3.2 mm steel plates were 1.97 and 2.36 times larger respe ctively, than that of the laminated wood. Their average MOR values wer e 1.42 and 1.54 times larger respectively, than that of the laminated wood. Five-and six-meter long composite laminated woods, 15 cm in brea dth, 20 and 25 cm in heights, also were manufactured, and bending stre ngths are discussed. Measured MOE values also agreed with estimated on es. The specific gravity of 0.49 of six-meter long composite laminated woods was not more than that of Douglas-fir (Pseudotsuga menziesii) l aminated wood. Composite laminated woods with finger-jointed lamina in tension lamination had ultimate bending strengths after the finger-jo int lamina broke, whereas the ultimate strength of similer sized compo site laminated woods without finger-joint lamina were less strong beca use the tests were stopped when the lamina of tension lamination broke . Delamination without wood falure did not occur during all of the ben ding tests. The average MOR value of composite laminated woods of larg e scale were more than 6,174 N/cm(2) (630 kgf/cm(2)), and that of the MOE value was 14.6 GPa (149 x 10(3) kgf/cm(2)).