Strength properties of sugi (Cryptomeria japonica) grown in Akita Prefecture V. Production and performance evaluation of the glulam

We examined the method used to produce glulam for structural use from sugi (Cryptomeria japonica D. Donn) that is produced in Akita Prefecture. These studies have been reported in the Ist similar to 4th papers. The aim of thi s report is to examine these studies comprehensively. We produced 10 ply an d 14 ply glulam. Then we evaluated the performance of laminae and examined reasonable production conditions of the glulam. Furthermore, these full-sca le glulams were tested for mechanical properties in bending load and predic ted the performance by simulation. The performance of glulams, which were produced this time, correspond to th e E75-F240 grade of glulam in JAS. However, as a result of prediction bq si mulation, there a ere some glulams, which did not correspond to the strengt h standard. For this reason, we carried out the simulation again with the c ondition that proof-loading test was carried out to laminae. As a result. t he performance of glulams was almost able to achieve the E75-F240 grade. The average mechanical properties of both glulams composed by the 4-grade m ethod (based on a composition of JAS) and the 3-grade method were almost th e same. However, in the glulam composed by the 4-grade method, the yields o f lamina were about 60%.