Structural Analysis and Optimisation of Low-Cost Greenhouse Designs for Year-Round Vegetable Production in Nigeria

This study conducts structural analysis and optimisation of low-cost greenhouse designs for year-round vegetable production in Nigeria, addressing the need for structurally adequate, affordable protected cultivation infrastructure suited to Nigerian climatic and material supply conditions. Protected cultivation under greenhouse structures offers significant advantages for Nigerian vegetable production including pest and disease protection, year-round production, and water use efficiency. However, existing greenhouse designs used in Nigeria are primarily imported or adapted from temperate country designs that may not be optimally structured for Nigeria's wind load, thermal environment, and local material availability conditions. This study performs structural analysis of three low-cost greenhouse frame configurations, bamboo frame, local timber frame, and cold-formed steel, using finite element analysis with wind and dead loads calibrated to Nigerian climatic zones. Material cost, fabrication complexity, and durability are assessed through supplier surveys and prototype testing. Year-round microclimate performance is modelled using EnergyPlus building energy simulation software. Performance validation is conducted using an instrumented prototype greenhouse at the Federal University of Agriculture Abeokuta. Findings reveal that cold-formed steel frames provide optimal structural performance at moderate cost, while bamboo frames are adequate for light-wind southern zones and offer the lowest material cost. Internal temperature management through evaporative cooling pads is essential for productivity in the dry season at all Nigerian locations tested. The study recommends differentiated greenhouse design standards for Nigeria's six agro-ecological zones.

Keywords: greenhouse design, structural analysis, protected cultivation, Nigeria, low-cost structures.