Understanding API ICP653 Reading 7-Worksheet-04 Part1

B.2.3 Edge settlement
B.2.3.1 Occurs when tank shell settles sharply around the periphery, resulting
in deformation of the bottom plate near the shell junction. (See Fig. B-4 for
pictorial view).
B.2.5 Localized Bottom Settlement (Remote from Shell)
B.2.5.1 Depressions/bulged that occur in a random matter, remote from shell.
B.2.5.2 Acceptability dependent upon:
a. Localized bottom plate stresses.
b. Design/quality of lap welds.
c. Void severity below the bottom plate.
NOTES:
1. Not normally seen as extreme problem.
2. When occurring, normally associated with new tank where no or insufficient
load bearing soil test borings have been made.
Charlie Chong/ Fion Zhang