Structural Behavior Of Column-Supported Steel Silos With A Transition Ring

Steel silos for the storage of bulk solids generally consist of a cylindrical vessel above a conical discharge hopper. Internal pressures and downward frictions produced by bulk loads lead to the meridional tension at the top of the hopper, and the tensile force attains the maximum at the cone-cylinder transition junction. The horizontal component of the tensile force leads to a large circumferential compressive force at the transition junction, and a ring (named transition ring) is often provided to strengthen the junction. While many studies have been conducted on uniform-supported steel silos with a transition ring, no systemic study was carried out on column-supported silos.Numerical methods were adopted in this thesis to investigate the stability behavior of two kinds of column-supported steel silos with a transition ring commonly used in light steel silos, including column-supported silo with columns terminating at the ring and with columns extending to the silo wall.Linear stress analyses were performed to investigate the stress-strain distribution of two kinds of column-supported steel silos under bulk loading. Linear eigenvalue buckling analyses (LEA) were performed to investigate the stability behavior of the structure and to find out the principal parameters governing the buckling loads and buckling modes of the silo.Geometrically nonlinear analyses (GNA) were then performed to examine the loading-deformation response of two kinds of silos, and to study the effects of various geometric parameters, such as the width of the column and the dimension of the ring. It is found that the buckling strength of the structure is mainly dependent on the width of the column, while the ring size of the silo just affects the local buckling of the ring and limited influence on the whole buckling strength of the silo. As the post-buckling behavior of the ring is stable, it is safe to take the ring buckling as structural design control.Geometrically and materially nonlinear analyses (GMNA) were carried out to analyze the effects of several geometric parameters on the elastic-plastic behavior of the structure. The R/t ratio of the cylindrical shell is found to be a main parameter that affects the plastic range and the buckling strength, and the column width also affects the bucklingstrength.Eigenmode-affine geometric imperfections were introduced in both GNA and GMNA of two kinds of column-supported silos to analyze the effects of imperfections on the stability behavior of the structure. In general, two kinds of silos were not sensitive to eigenmode-affine geometric imperfections, especially the silo with columns extending to the silo wall.