Why Are Grain Silos Cylinder


Take a drive through the countryside or along any highway through the Midwest, where grain is most abundantly grown, and you'll see the tall, cylinder shapes that rise above the horizon. It's a sign that a grain-producing farm is near. But silos aren't built round for their monumental value. They are built as cylinders for practical reasons, ranging from cost to efficient land use.

Save Space
Round silos make full use of the land needed for the storage building.  Land costs money, but the sky is free, so the round silo also save money.The tall shape contribute to storage and dispensing.

Fewer Joints
For a cylindrical silo, there are joints only along the foundation and the conical top, which should be fitted tightly for two reasons. First, it increases the rigidity of the walls. Second, it makes the silo airtight and easier to fumigate. Square or rectangular structures have joints at every corner, making sealing and fumigation more difficult. Sealing the harvest from outside weather is important to prevent spoilage. Also, harvested grain attracts rodents and insects, so buildings with fewer joints give the pests fewer spaces through which they can enter.
Most people consider grain in terms of weight, tension and pressure, but when you harvest corn, all those kernels add up to tons and tons of weight. That weight not only exerts pressure on the bottom of the stored grain, but also on the sides of the steel silo that hold it. The outward forces are known as hoop tension forces, which are more efficiently contained through steel reinforcement of the walls. Weight compression also creates heat, adding more pressure to the building. A square or rectangular structure would have to resist bending pressures, and their foundations would have to resist the overturning forces that can be caused by grain loads. By comparison, cylindrical structures are built more to resist the vertical pressures.