Original paper(Vol.47 No.6 pp.631)
Properties of compressive strength parallel to the grain of structural glued laminated timber composed of homogeneous-grade lumbers of Japanese larch
Kadowaki Taro; Takeda Takashi; Hashizume Takeo; Tokumoto Morihiko
Abstract:It is known that bending strengths of glued laminated beams (glulams) may be dominated by tensile strengths of outer layers of glulams. Since compressive strengths as well as tensile strengths of laminate should effect the stress distribution through the depth of the beam, the compressive strength may be important to estimate the bending strength of the beam. In the present paper, we considered about the effects of number of laminate on compressive strengths of glulams composed of homogeneous grade lumbers of Japanese Larch.
We conducted compression tests parallel to the grains with various number of laminate and different grades of glulams. The test results showed that the effect of lamina grades on the mean compressive strength (CS) were clear and the correlation between the mean CS and specific gravity (SG) were considerably high. We calculated the ratio of compressive strength to specific gravity, so called 'specific strengths' (SCS). The effects of lamination on mean CS and mean SCS were not observed for both high and low grade glulams, then the size effects on CS and SCS were very small. We compared these test results to bending strength (MOR) done in the previous paper.
Key Words:glulam, Japanese larch, mechanical grading, compression strength, short column