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In recent years, whole steel frame steel greenhouses have become increasingly prevalent. With the characteristics of large flexibility and small mass, whole steel frame steel greenhouses are sensitive to wind loads. However, studies on the safety of whole steel frame steel greenhouses under wind loads are still limited. In this study, a 10 m span whole steel frame solar greenhouse was taken as the research objective. Taking the Davenport spectrum as the target spectrum, the time history of the wind speed was simulated by the harmonic superposition method. The finite element model of the greenhouse structure was established using ANSYS software. The simulated wind pressure was applied on the greenhouse structure for dynamic response analysis. The dynamic response results were compared with the static analysis results under average wind load. The results showed that the greenhouse structure mainly bears bending stress under wind load. The bending stress, axial stress and displacement of the greenhouse skeleton under average wind loads are lower than those under instantaneous wind loads. It is necessary to consider the dynamic characteristics of wind loads in the design of solar greenhouses. A wind-induced vibration coefficient is obtained, which can be used to convert the dynamic load into the equivalent static load and improve its design efficiency.

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To investigate the characteristics of grape transpiration water consumption and its environmental coupling mechanism in a greenhouse growing environment in cold areas of Northeast China, the dynamic monitoring of greenhouse grape sap flow and microenvironmental factors in a greenhouse was carried out for two years. Correlation analysis and path analysis were used to study the characteristics of grape transpiration environmental factors at different temporal scales (instantaneous, daily, and growth period) and the influence mechanisms on greenhouse grape transpiration. The results of correlation analysis by growth period showed that, on the instantaneous scale, the correlation between each meteorological factor and grape transpiration reached a significant level (coefficient of determination R2 ranged from 0.25 to 0.84). On the daily scale, the correlation of solar radiation (Rs) was the best except for the new growth period (R2 ranged from 0.49 to 0.89). The results of the split-fertility path analysis showed that the total effects of Rs on instantaneous transpiration were the largest at all stages of fertility, with decision coefficients (R) ranging from 0.69 to 0.90. On the daily scale, the total and direct effects of Rs on daily transpiration were the largest (R ranged from 0.70 to 0.94), except for the new growth period. The results of the whole growth period path analysis showed that Rs had the greatest effect on instantaneous transpiration, with R of 0.86. On the daily scale, Rs was also the most influential factor in grape transpiration, with R of 0.81. On the growth period scale, only air temperature (Ta) and leaf area index (LAI) were significantly correlated with transpiration (p < 0.05), and Rs had the largest total effect on transpiration with R of 0.68. To sum up, on each time scale, Rs was always the most important factor influencing grape transpiration. However, as the time scale increased, the effects of LAI and soil water content (SW) on transpiration increased while the effects of Rs, Ta, RH, and VPD on transpiration gradually decreased.

The test of four rubber concrete filled steel tube (RuCFST) members, one concrete filled steel tube (CFST) member and one empty member were conducted under pure bending. The main parameters were the shear span ratio (λ) from 3 to 5, and the rubber replacing ratio (r) from 10% to 20%. The bending moment-strain curves, the bending moment-deflection curves and the bending moment–curvature curves were obtained. The failure modes of core rubber concrete were analyzed. The failure mode of RuCFST members was bending failure from the results. The cracks of rubber concrete were distributed evenly and sparsely, and the filling of rubber in core concrete prevented the development of cracks. The shear span ratio has little effect on the behavior of the tested specimens. While the rubber replacing ratio had little effect on the bending moment capacity, but had some influence on the bending stiffness of the tested specimens. After filling in rubber concrete, the bending moment capacity and the bending stiffness can be improved compared with the empty steel tube specimen.