Study On Stability Behavior And Strength Of Column-Supported Steel Silos With Engaged Columns

Supporting silo walls directly on engaged columns provides a simple and cost-effective support arrangement for light steel silos. Several brief provisions about it have been provided in Eurocode 3, but no systemic study has been carried out on structure behavior of these silos. As a type of combined thin-walled shells of revolution on local supports, the structure behavior and failure criteria of silos supported on engaged columns are very complex.Numerical analyses including linear stress analyses, linear eigenvalue buckling analyses, geometrically nonlinear analyses, geometrically nonlinear analyses with imperfections included, geometrically and materially nonlinear analyses are carried out to investigate the stability behavior and strength of these column-supported steel silos with engaged columns.At first, linear stress analyses were performed to investigate the stress-strain distribution of axially compressed column-supported steel silos with engaged columns. A series of 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 load of the silo.Geometrically nonlinear analyses (GNA) were then performed to study silos of various geometric parameters, such as the R/t ratios of the cylindrical shell, the heights of the engaged columns, the heights of the cylindrical shell and the width of the column. It is found that the buckling strength of column-supported silos is mainly dependent on the height of the engaged column, which also affects the buckling deformation mode. The R/t ratio of the cylindrical shell is also a main parameter that affects the buckling strength of the silo. For silos of various R/t ratios, the buckling strength will increase while the engaged columns are extended towards the top edge of the shell and the trend are similar. It is possible to take the shell rotation as an easily applicable failure criterion of silos in practice.Next, two patterns of initial geometric imperfections including circumferential welding depressions and eigenmode-affine imperfections were introduced in the geometrically nonlinear analysis. The effects of the location and amplitude of the imperfection were investigated. It is found that both the two patterns of imperfections can lead to a significant reduction in the buckling load of the silos in some specificcases. So the effects of initial geometric imperfections should be taken into account in the design of silos with engaged columns.At last, geometrically and materially nonlinear analyses {GMNA) were carried out to analyze the effects of several geometric parameters on the elastic-plastic behavior of the column-supported silos. The height of the engaged column is still found to be a main parameter that affects the stability behavior of the silo.