Obliczenia wytrzymałościowe

 

Silo loads

 

   In this article we spend some time on silo loads considering. Generally calculations according to standards are quite complicated. In order to understand the idea of determining silo loads we focus on simple linear equations. In case of squat silos linear equation often gives satisfactory approximation. The problem is in slender silos where linear equations cause overestimation of the loads acting on silo walls. Linear distribution is presented below for squat silo and nonlinear distribution for slender silo.

 Silo load

Fig. 1. Pressure due to stored particulate solid in squat and slender silo

 

Let's focus below on linear pressure distribution.

Horizontal pressure acting on vertical walls at "y" level is equal: 

 

py = px · tg2 (45-φ/2)

where: px - vertical pressure in stored particulate solid at "y" level, so it is equal:                 

                

px = γ · y

gdzie: γ - unit weight

          φ - angle of repose

 

Pressure normal to hopper wall is calculated as below:

pa = px · cos2α + py · sin2α

 

Above pressures are presented at picture below:

Pressures in silo

Fig. 2. Pressure distribution at vertical wall and hopper

 

Angle of repose φ for typical solids are prestented below:

Angle of repose

 Fig. 3. Angle of repose example