Development and Application of Self-building Bamboo Structure for a Greenhouse

-Case study on “Kumano Bamboo Greenhouses” in Kumano city, Mie Prefecture-

Abstract

The objective of this study was to develop a self-bulidable greenhouse using bamboo to decrease cost for material and building work. Small-scale experimental Bamboo Greenhouses (BGHs) were built in Ikusei-cho, Kumano city, Mie prefecture. Materials costs for both BGH No. 1, resembling an even-span greenhouse, and BGH No. 2, resembling an Quonset style greenhouse, were approximately 160 000 yen/a. This is approximately half that of a steel-pipe house. BGH No. 1 and BGH No. 2 could be built in 364 and 267 hours, respectively. The calculation of structural strength is diffi cult because of the variability of dryness and degradation of bamboo materials. However, critical damages have not been observed in either BGHs during the 47 months post-construction. As for the ability for heat retention, the average daily temperature inside of the BGH was 2.5 °C higher than the ambient temperature in winter. 　　From these results, it is found that the costs of materials in BGHs were lower than that of steel-pipe house, and that BGHs can be self-built at a small-scale, irregular-shaped farmland. Continuous observations of bamboo strength will be conducted to determine the number of durable years, and a simpler method for assembly of the bamboo structure may be developed. 　　Moreover, cutting bamboo for the maintenance of abandoned bamboo groves will help to prevent animal damage and to conserve the traditional landscape of farming and mountain villages.