Seismic performance analysis of Dutch Venlo greenhouse structure

A Venlo-type greenhouse has widely been introduced from Netherland for modern agriculture in China at present. This type of greenhouse is also the largest, most commonly-used, and state-of-the-art glass structure with advanced equipment and control systems for super greenhouses in the world. However, few national standards are released for the structure design of modern agricultural greenhouse, although most industry or group standards in China. Furthermore, the combination of earthquake load other than wind load cannot be usually considered for the structure design in most studies, due to the light-weight components and covering materials in the greenhouse structure. If the greenhouse that designed by the Netherlands was directly introduced to adopt the Dutch structural standards in China, there is a safety hazard of seismic action for the damage of main structure, particularly for nearly half of land areas in high-level zones of seismic intensity in China, even above 7 degrees. Taking a Venlo-type greenhousedesigned by a Dutch company in Shandong province as an example, this study aims to explore the impact of seismic action on structural safety according to the Dutch code, considering the stress diaphragm of covering material on the structural stiffness. A finite element software MIDAS Gen with the response spectrum modal was also selected to simulate the whole structure of the greenhouse with the seismic precautionary intensity of 7 (0.10 g), 7 (0.15 g), 8 (0.20 g), and 8 degrees (0.30 g). A systematic analysis was made on the mode periods, vibration patterns, the maximum stresses, and displacements for the structure. The results showed that the longest period of natural vibration was 1.75 s in the greenhouse structure, indicating a relatively flexible performance of the structural system. The first and second vibration patterns were the flat motion in Y and X -direction, especially a similar seismic performance in the 2 principal axes. Additionally, the maximum bearing capacity of the structure was 216.96 MPa for different seismic precautionary intensities under the wind load. The maximum stress was still less than the yield strength of components. When the seismic precautionary intensity exceeded 8 degrees (0.30 g), the maximum tensile and compressive stresses of components were 211.95 and 196.02 MPa for the X-directional seismic action, respectively. In addition, the maximum displacement was 31.80 mm under the X-directional wind load without considering seismic action. The structural deformation was also mainly influenced by the seismic load. Specifically, the Y-directional seismic action was about 11.6% than that in the X-direction under the same load combination. Consequently, the greenhouse structure introduced from Netherland can always be expected to fully meet the code requirements within the elastic range of components, when the seismic intensity was lower than 8 degrees (0.30 g). Nevertheless, the maximum deformation exceeded the standard requirement of 1/250 of the elastic inter-story displacement angle, according to the code for seismic design of buildings in China.