Section IV.3
**
Section
IV.3 Single
Cell-
Multiple
Flange
Beams: Symmetric and Unsymmetric Cross Sections
**

This section deals with statically indeterminate box beams with constant-shear-flow webs. For
example, a single cell box beam with four stiffeners and four webs.
The shear flow analysis in such box beams is
basically the same
as that discussed in section IV.1
for closed sections.
We cut the cross section at a particular web in order
to start the solution at a point with a known shear flow (i.e., q' = 0), and
work around the cross section using the general shear flow equation.
Then, we replace the cut web and show a constant shear flow qo around the
closed cell. This unknown shear flow is the actual value of shear flow
in the web that was originally cut.
Both the shear
center and direct method can be used to solve for the unknown shear flow.
The shear flow between stringers can
be calculated as in section III.6. Remember
that for these problems, the shear flow between two adjacent stringers is
constant in both magnitude and direction. The change in direction can only
occur at a stringer location.

The example below shows the analysis procedure.

EXAMPLE
PROBLEMS

- Example 1 Shear flow distribution
and shear center location of a single-cell multiple-flanged box beam

To Section
IV.4
To
Section IV.2

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Transverse Shear Loading of Closed Sections