Analytical model for the design of performance in glulam beams of Japanese cedar .1. Prediction model for flexural strength including the effect of the reinforcement by laminating and of the plastic deformation in the compressive zone

The aim of this study was the development of the design method of performance in glulam beams of Japanese cedar (Crytomeria japonica D. Don). An analytical model was made for predicting the modulus of rupture (MOR) of glulam beams, and a Monte Carlo simulation was made. Models of rupture were based on the following three conditions: the first was determined by the MOR of lamina; the second was done by the tensile strength (TS), and the third was done by both of them. The predicted distributions of MORs of glulam beams simulated by this model did not agree well with the experiental data of bending tests. Therefore the model was improved considering the effects of reinforcement due to laminating and of plastic deformation in the compressive zone because Japanese cedar of mediumsize has many weak points suchas knots and smell compressive-yield strength. The laminating effect was estimated by the stochastic process theory of fracture, and the plastic deformation was modeled by Kon's model. The predicted results by means of the new model agreed well with the experimental results.