Development of a structural analysis model for pipe structures to reflect ground conditions

Recent climate change and the increase in unpredictable meteorological disasters has continue to damage greenhouses. Although structural safety standards have been established, they do not fully reflect the environment where greenhouses are installed. Existing standard greenhouse designs assume that the boundary conditions are fixed, even though the real boundaries move due to the absence of foundations. In this study, a structural analysis model was developed that reflects the ground conditions for pipe structures installed without a foundation, and their structural safety was reviewed under various levels of snow load. The structural analysis model was developed by applying the prescribed displacement and rotation boundary, using values derived from an experiment that was performed considering loading and ground conditions. The developed model was compared with the existing methods considering only fixed and hinged boundaries by examining the bending moments and the axial forces. As the boundary at the ground moved according to the applied load, the maximum bending moment reflecting the ground conditions was larger than the result from the fixed boundary. Additionally, as the load is gradually increased, the stress calculated reflecting the ground conditions was larger than the result from the hinged boundary. Safety review indicated that the marginal snow depth that could be sustained by the structure decreased by up to 25% when the ground condition was reflected. These results suggest that the current structural analysis methods applied to pipe greenhouse structures with no foundations could lead to the structure being under designed.