The Development of a Rain Storage System for Highland Agriculture Using Lightweight Composite Sandwich Panels

The Royal Agricultural Projects in the Mountains of the northern provinces of Thailand operate under challenging conditions while trying to set examples of sustainability, especially by minimizing the impact of farming on the local ecosystem and the uniquely beautiful landscape. Managing water, which exists in over-abundance during the rainy season and is very scarce during the rest of the year, is a very demanding task, if using electric power for pumping and building multitudes of reservoirs into the landscape are no options. A flexible water storage system has been developed to satisfy a specific set of design constraints, including the option to install the containers on elevated levels inside green-houses or unprepared ground, and the possibility to install and de-install the storage units multiple times without heavy machinery, as well as being in line with the overall motivation of maximized sustainability as well as minimized complexity and lifecycle costs. A proposed concept uses composite sandwich panels as structural elements, which are integrated into the overall structure without any connectors or sealing measures to satisfy all practical demands. This paper derives the design rationale from a functional discussion. It covers the finite element simulations and the experimental testing of the mechanical properties of the employed sandwich material (stainless steel faces, PU-foam core) and the validation of the supporting steel structure. Two containers with a capacity of 27,000 liters each were built and tested on-site.