Page 248 - Pressure Vessel Design Manual

226 Pressure Vessel Design Manual

L

Figure 4-14. Dimensions and loadings for various ring girders.

e Moment for semi$xed span.

B,L~
M=-
Additional bending in base plate, 10
Additional bending occurs in base plate due to localized e Bending stress, fb.
bearing of post on ring.
6M
Bearing pressure, B,, psi fb =-
t2

Notes
where A = assumed contact area, area of cap plate or ~
cross-sectional area of post. See Figure 1. The shell of a column-supported tank, vessel, or bin is
4-14. Assume reaction is evenly distributed considered to be a “circular girder” or “ring beam”
over the contact area. uniformly loaded over its periphery and supported by
l = Cantilever, in. columns equally spaced on the ring circumference.
L = Semifued span, in. 2. The ring beam (girder) is subjected to compression,
bending, and torsion due to the weight of the tank and
Note: Maximum bending is at center of base plate. contents and horizontal wind or seismic force.
3. The maximum bending moment occurs at the sup-
e Moment for cantilever portion. ports.
4. The torsional moment MT will be 0 at the supports
BPI2 and maximum at angular distance fl away from sup-
M=- ports.
2