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04.12: Analysis of silo supporting ring beams: Resting on discrete supports
Author(s) -
Zeybek Özer,
Topkaya Cem,
Rotter J. Michael
Publication year - 2017
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.132
Subject(s) - silo , ring (chemistry) , engineering , chemistry , mechanical engineering , organic chemistry
Silos in the form of a cylindrical metal shell are often supported on a ring beam which rests on discrete column supports. The function of the ring beam is twofold. First, it is required to carry circumferential forces to maintain equilibrium at the transition junction between the cylinder and hopper. Second, the ring beam plays an important role in redistributing the majority of the discrete forces from the column supports into a more uniform stress state in the cylindrical wall. The Eurocode EN 1993‐4‐1 [1] only provides design equations for stress resultants produced in the isolated ring beam under uniform transverse loading. This paper explores the extent to which a practical silo shell causes these stress resultants to be reduced when the ring beam has only practical stiffness. The behaviour of a ring beam which interacts with the silo shell is much more complex than that of an isolated ring beam. In traditional design treatments, it is assumed that the discrete support forces are redistributed entirely by the ring beam to provide circumferentially uniform axial membrane stresses in the silo shell. But this assumption is only even approximately valid if the ring beam is much stiffer than the silo shell [2]. Since the cylindrical shell is very stiff in its own plane, the ring beam that responds with both flexure and twisting must be remarkably stiff to be stiffer than the shell. A ring beam stiffness ratio was previously developed by the authors to find the requirement for the ring beam stiffness to meet this traditional role [2]. This paper presents a new study to explore the ring beam stress resultants when closed section ring beams of lower stiffness and practical dimensions are used. A finite element parametric study is undertaken to explore the stress resultants and displacements in more flexible ring beams connected to a silo shell. The results show that the level of reduction from the isolated ring beam values can be directly related to the ring beam to shell stiffness ratio.