Bending Properties of Mixed-Species, Three-Ply CLTs (Cross-Laminated Timbers) with Inner Layer of Sugi

Abstract

Two types of mixed-species three-ply CLTs （Cross-Laminated Timbers） composed of hinoki-sugi-hi-noki and akamatsu-sugi-akamatsu were manufactured in this study. The relationships between modulus of dynamic elasticity using frequency （(cid:9481) fr ） of logs or lamina graded visually for knots, and modulus of elasticity （MOE） of edge-glued laminae were investigated. Moreover, mixed-species three-ply CLTs were examined by static bending tests to clarify the bending properties. The results are summarized as follows : Positive correlations were recognized between (cid:9481) fr of logs and MOE of edge-glued laminae for each species. When comparing average values of MOE of edge-glued laminae graded visually for knots, it was recognized that for sugi and akamatsu, MOEs of edge-glued laminae with none or fewer knots were significantly larger than those with few knots and loose knots. MOEs for mixed-species three-ply CLTs were clearly greater than those for sugi-only three-ply CLTs. When comparing mixed-species three-ply CLTs with hinoki or akamatsu single species three-ply CLTs, air-dry densities for mixed-species three-ply CLTs were significantly lower. However, differences of MOEs between mixed-species three-ply CLTs and hinoki or akamatsu single species three-ply CLTs were hardly recognized. : sugi, edge-glued lamina, mixed-species, CLT, modulus of elasticity.