Seismic performance analysis of Venlo greenhouse in shaking table test

Greenhouses have been widely used in facility agriculture at present. Gutter-connected greenhouses have been also extensively implemented to enhance the structural span for high land utilization with simplified mechanization. Among them, Venlo greenhouse has been the preferred choice among various forms of roof trusses, due to the simplified installation, superior light transmittance, and excellent sealing. The "National standard for the design of greenhouse structure " also released that "seismic action shall be calculated in the structural design of glass greenhouse for agricultural production in areas with seismic fortification intensity of 8 degrees (0.30g) and above". In this study, a regular-shaped Venlo-type greenhouse was designed to investigate the seismic performance and response using a shaking table test. A scaled-down model was then established with one span and two openings. The dynamic features of the modeled structure were analyzed to determine the acceleration response of the structure under the action of the 7-degree frequent, 7-degree fortification intensity, 7-degree rare, 8-degree rare, and 8-degree semi-rare earthquake. Numerical simulation was carried out in conjunction with finite element (FE) ANSYS software. The test and simulation were compared to verify the reliability of dynamic time-range analysis. In addition, the numerical model was established, according to the structural design of a Venlo greenhouse project. The time-history analysis was carried out under the action of 8 degrees and half rare earthquakes (the maximum acceleration time history was 0.51g). Meanwhile, the combination of permanent, snow, and crop load was selected, according to the specification. Three groups of seismic waves (namely AKT, NGA, and artificial wave) were input into the structure of the greenhouse. The mode of structure was analyzed to determine the internal force, vibration pattern and displacement with/without the action of the seismic waves. The results show that the maximum stresses in the overall structure of the greenhouse under seismic action were 1.24-2.12 times higher than those under no seismic action. The structural stresses during the action of artificial waves exceeded the yield strength of the material. Two cases (b1 and b2) were applied under the action of the same set of seismic waves. The b1 case was adopted to combine the live load with crop and snow loads, whereas, the b2 case combined the crop load only. There were similar values in the column top displacements. The seismic action dominated the column top displacements in these cases. The maximum displacements occurred in the outside wall storm columns. The largest displacement response was observed at the top of the structural columns under the action of artificial waves. The maximum of up to 72.17 mm exceeded the standard requirement of 1/250 of the elastic inter-story displacement angle for the seismic design of Chinese buildings. The research results can provide a theoretical reference for the safe design of Venlo greenhouse under seismic action.