Prediction of Bending Properties of Lightly Modified Bamboo from Bambusa blumeana

Abstract

Bamboo is one of the most sustainable construction materials in the world. A new form of bamboo material called "mass bamboo panels" has been developed for wall and floor systems for multi-story buildings. Mass bamboo panels use lightly modified bamboo (LMB) where the top and bottom of round bamboo are flattened to create gluing surfaces. Mass bamboo panels use layers of LMB in different configurations to create beams and panels. Currently, no studies of the mechanical properties of the LMB have been performed. The goal of this project was to predict the mechanical properties of LMB based on experimental testing and analytical models. First, whole culms of Bambusa blumeana were measured and tested non-destructively in bending. Then, the culms were processed into LMB of three different thicknesses. After processing, the control round bamboo and the LMB were tested destructively in bending. Prediction methods for the strength and stiffness of LMB included the use of single variable correlations and best subset multiple regression model. From the single variable correlation and best fit multiple linear regression models, the strongest predictors for the bending strength and stiffness were the non-destructive bending modulus, and variations of average diameter. Though the predictive power was lower for bending strength and maximum moment terms, the flexural stiffness and modulus of elasticity were well predicted. Among the LMB groups – bending stiffness and maximum moment significantly decreased with LMB processing while modulus of elasticity and bending strength did not. The percent loss of stiffness was well predicted by the percent loss of mass removal and depth removal of the LMB with a stiffness decrease of 2.49% and 2.44% for every percent change in mass and depth reduction, respectively.