Mechanical properties of covering materials for greenhouses .2. General overview

Covering materials of greenhouses in use today in Europe are classified and analysed with respect to their use. Glass still appears to be one of the most widely used materials in Northern Europe. However, the development of new plastic materials has led to a significant increase in the overall share of plastic covered greenhouses in Europe and their complete domination in Southern Europe. The mechanical properties of greenhouse coverings are very important in relation to their mechanical behaviour under various loading conditions and to the overall structural behaviour of the greenhouse. The ultimate design of a greenhouse has to represent a balance between the overall structural design, the mechanical and physical properties of the cladding materials and the specific agronomic requirements of the crop. Installation of the covering materials to the greenhouse structure plays an important role in the overall mechanical performance of the covering. Another important factor affecting the mechanical behaviour of the covering materials of greenhouses is the environment. In general, the mechanical properties of the covering materials of greenhouses (combined with the physical properties) are found to be critical in determining the relevant requirements concerning the structural design and construction details of a greenhouse. (C) 1997 Silsoe Research Institute.