Silo Discharge Design and Construction Influences on Wall Pressures

A silo structure relies upon its capacity to resist hoop stresses within the silo’s corrugated steel wall. Designs are based upon the silo’s ability to remain circular in shape. An internal wedge hopper design is analyzed to determine the effect of soil consolidation under the soil wedge and resultant wall pressure distribution. An internal wedge hopper consists of compacted soils beneath a concrete slab within the constructed steel wall. Techniques used to analyze the soil/structure interaction upon the silo walls are discussed as a basis for determining the resultant shape, i.e., roundness, and state of stress of the silo wall structure. The analysis indicates the integrity of the silo is a function of construction practices including lift sequencing and degree of compaction of soil placed for the construction of the wedges. While the completed construction of a silo may comply with design specifications, placement of bulk storage materials within the silo may change the state of stress, out-of-roundness, affecting the performance of material handling systems, or worse, cause catastrophic failure of the silo.