Determining pressure coefficients due to wind loading on grain bins

Wind loading is one of the factors that must be considered in structural analysis and design of grain bin structures. Structural design codes and handbooks in the U.S. only provide limited information about the local distribution of wind pressure on grain bins and conical roofs. This lack of reliable design data has contributed to wind-induced problems with these structures.; An experimental study was conducted to determine the effects of wind-induced pressures on the walls and the roofs of grain bin structures. The main objective of this research was to establish wind pressure distributions and thus pressure coefficients due to wind loading for grain bins with conical roofs. To achieve this goal, we conducted a series of wind tunnel experiments in a boundary layer wind tunnel using model grain bins with various sloped roofs and aspect ratios. The 1:60 scale model bins with variable height to diameter ratios of 1.0, 1.5, and 2.5; and four different roof configurations with angles of 25°, 30°, 35°, and 40° were used for pressure coefficient measurements of isolated bins in the wind tunnel. In addition, the effects of bin groupings were also investigated by running experiments with three different bin-grouping configurations. Grouping configurations were tested with a 30° roof, and a cylindrical wall with an aspect ratio of 1.0 at wind directions of 0°, 45°, and 90°. The mean pressure coefficients were calculated for each roof angle and cylindrical wall. In addition, a 4 m high and 4 m diameter full-scale bin was constructed in the field and wind pressure measurements were conducted with necessary instrumentation under natural wind flow conditions. Pressure distributions and pressure coefficients were determined based on wind speed and direction.; At the end of experiments, pressure coefficient data (Cp) were available for the walls and conical roofs of both model and full-scale bins. Contour plots of the data were drawn for each conical roof to be used as guidance tools in the design and analysis of grain bins.