Simple structural concepts for cylinders

The chief goal of predicting pressures in silos is to ensure the safety of the structure. So the effect of the pressure on the structure must be a key element. All early studies of pressures assumed that the simple equilibrium between normal pressure and hoop (circumferential) 

Adopting Janssen s theory for the pressure pattern, the resulting axial force per unit circumference developing in the silo wall under symmetrical conditions is then 

The above theory for cylinders is not valid for conical hoppers. For them, even the simplest stress analysis is much more complicated and is beyond the scope of this chapter. More information may be found in Rotter (2001a). 

In reading what follows it should be noted that metal silos are most sensitive to vertical compression in the vertical walls, that concrete silos are most sensitive to normal pressures against the walls, and that both of these structural materials are easily damaged by unsym-metrical pressures, as noted in Sections 3.4.5 and 3.5. Finally, the hopper, which has not been discussed yet, is usually chiefly loaded by the vertical stress in the solid at the transition. These different sensitivities demand that careful attention is paid to different parts of the pressure theory, since it is not normal wall pressures alone that cause structural failures. 

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