Structural Grading and Characteristic Value of the Moso Bamboo Culm Based on Its Minimum External Diameter

Abstract

Bamboo culm has been regarded as a traditional element in construction; meanwhile, it has great potential for the construction of rural houses to achieve green and low-carbon development. However, traditional bamboo houses are usually constructed according to previous experience, and it is hard to design bamboo houses in a standard way. Structural grading of the bamboo culm is an essential work to achieve standardization design. Grading the Moso bamboo culm (P. edulis) based on its minimum external diameter is proposed in this paper. The geometric, physical and mechanical properties of 883 Moso bamboo culms with three different treatment processes were measured and analyzed, namely untreated, with chemical preservatives and heat treatment. It was found that the external diameter of the Moso bamboo culm could be determined by the perimeter in practice. The treatment process has a great influence on the geometric, physical and mechanical properties. Bamboo culms with three different treatment processes could be divided into five, five and four grades, respectively. Meanwhile, based on measurement data, the characteristic values of each grade are presented, including the wall thickness, external and internal taper, linear mass, nominal density and compressive strength. The minimum chemical treatment factor is 0.785, 0.662 and 0.649, while the minimum heat treatment factor is 0.722, 0.644 and 0.877 for wall thickness, linear mass and nominal density, respectively. The treatment factor for compressive strength is 1.12 and 1.52 of chemical treatment and heat treatment, respectively. This study may aid establishing technical specifications and a standard design method for Moso bamboo structural building.