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U.S. Department of Energy
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Stress analysis of a double bottom retrofit of an aboveground storage tank including effects of soil/structure interaction

Conference ·
OSTI ID:176079
;  [1]
  1. BP Oil Co., Cleveland, OH (United States). Engineering Services

Concern about differential settlement of aboveground atmospheric storage tanks and the effects of the resulting large strains on tank floor integrity has become an important issue in the refining industry, prompting much of the industry to undertake massive programs to retrofit substantial numbers of existing tanks with second floors. This is normally accomplished by cutting a horizontal slot in the tank shell parallel to the existing floor, placing a liner and fill material (such as sand) over the existing floor, installing annular plates through the slot in the shell, and then welding in the remaining floor plate. In this process, the decision whether or not to weld the bottom side of the new floor plate to the shell stub attached to the original floor is a key design consideration which can significantly impact the stress distribution in both the new floor and the existing shell stub. Finite element analysis is used to study operating stresses in a typical double-bottom aboveground atmospheric storage tank on a raised compacted earth pad and gravel ringwall foundation. Results are compared for cases in which the new floor is welded to the existing shell stub and in which the new floor simply rests on the shell stub without further attachment. Effects of soil/structure interaction for a typical granular soil are included in the analysis.

OSTI ID:
176079
Report Number(s):
CONF-950740--; ISBN 0-7918-1346-0
Country of Publication:
United States
Language:
English