The two main characteristics of multi span film greenhouses are simple structure and flexible form. A simple multi membrane greenhouse is designed to remove some of the structures of a multi membrane greenhouse and is mainly suitable for grape greenhouses, strawberry cultivation, crop seedling cultivation, etc. It has the following two characteristics. In addition, the maintenance framework structure of multi span film greenhouses should be regularly maintained. The covering material should achieve the purpose of good lighting and insulation. Therefore, if strengthening measures are needed, leaks should be repaired in a timely manner.
The two major advantages of multi span film greenhouses are: (1) simple structure: due to the characteristics of the covering material, the load-bearing structure, film fixing system, and installation requirements of plastic greenhouses are relatively simple. The load-bearing structure adopts hot-dip galvanized light steel or ordinary steel structure, generally using hot-dip galvanized light steel structure. Steel structure is better in assembly structure. The main steel frame of the greenhouse is mainly composed of columns, perimeter beams, top arch bars, top tie rods, crossbeams, loose supports, gutters, etc. The use of top longitudinal bars as tie rods greatly simplifies the structure and reduces steel consumption. At the same time, when the greenhouse is covered with materials and the roof is not mechanically connected, the roof only bears gravity loads and positive wind pressure, and the wind pressure is transmitted to the gutter and columns, greatly optimizing the stress of the greenhouse structure.(2) Flexible and diverse dimensions: Due to the structural characteristics of connected greenhouses, the development of large-span connected film greenhouses has been influenced by various factors such as regional and customer demands. Countries around the world have launched production and promotion based on plastic greenhouses. Their respective standards have resulted in a large number of different forms and specifications of plastic film multi span greenhouses, such as high arched greenhouses with different spans, double arched greenhouses, serrated greenhouses, small arched multi span greenhouses, etc. Therefore, it is still difficult to summarize and describe the dimensions of individual plastic greenhouses. Therefore, the span and open space can be flexibly designed according to the needs of customers to meet the design requirements of different terrain sizes.
