Techniques for buckling experiments on steel silo transition junctions

Large elevated steel silos generally consist of a cylindrical vessel, a con ical discharge hopper and a skirt which may either be supported on the grou nd or by a number of columns. The cone-cylinder-skirt junction is subject t o a large circumferential compressive force due to the radial component of the meridional tension in the hopper, so either a ring is provided or the s hell walls are locally thickened to strengthen the junction. Many theoretic al studies have examined the buckling and collapse strengths of these junct ions, but no previous experimental study has been reported. This has been d ue to the great difficulties associated with testing these thin-shell junct ions at model scale. This paper first describes the development of an exper imental facility for testing model steel silo transition junctions. Issues covered include the fabrication of quality model junctions using thin steel sheets, the loading method and the precise three-dimensional measurement o f geometric imperfections and deformed shapes using a laser-displacement me ter. Typical experimental results of a cone-cylinder-skirt-ring junction ar e next presented to demonstrate the capability of the developed facility. P rocedures for processing the test results to determine both the buckling lo ad and the number of buckling waves are also presented. (C) 2001 Elsevier S cience Ltd. All rights reserved.