A MICROSCOPIC THEORY FOR PREDICTING LOADS IN STORAGE BINS FOR GRANULAR-MATERIALS

A two-dimensional model for predicting loads in granular material stor age bins was developed from the micromechanics approach, in which forc e equilibrium is considered at the particle (microscopic) level. The s ignificance of this approach is to allow some particle property parame ters to be used in calculations of stresses in storage bins for granul ar materials. Three key assumptions are made in the model: (1) the gra nular medium has a hexagonal structure consisting of elastic spheres, (2) rotation and slip of particles are negligible, and (3) stresses ar e uniform across the bin cross-section. Predictions by the proposed mo del are in close agreement with the experimental data reported by thre e different groups of researchers for maize and wheat storage bins. Ja nssen's equation, recommended by most design standards and codes, has been shown to be a special case of the present theory. The traditional assumption of constant lateral to vertical stress ratio was found to be valid only for frictionless walls or rigid particles. (C) 1996 Sils oe Research Institute