Section IV.2 Statically Determinate Stiffened Box Beams
**
Section IV.2
Statically
Determinate
Box
Beams with
Constant-Shear-Flow
Webs
**

The box beam shown in the figure below has three stiffeners and three
constant-shear-flow webs, as
a result, there are 6 unknown loads
(i.e., 3 shear flows qAB, qBC, qAC and 3 axial forces FA, FB, and FC).

Since for a non-concurrent, non-coplaner (general) force system we have 6 equilibrium
equations, we should be able to use these equations to solve for the 6 unknown
loads.

Hence, in **statically
determinate** box beams, we do not need to use the procedure involving the
general shear flow equation as described in previous section.

If we were to modify the box beam by including an additional stiffener, then
the problem becomes statically indeterminate as there would be 8 unknown loads
to solve for as opposed to 6 in the previous case.

Under these conditions,
we rely on the procedure described in the previous section based on the
general shear flow equation. The solution procedure becomes
much simpler, however, as the shear flow along each web is constant.

The example below describes the method of solution for statically determinate
stiffened box beams. The discussion of statically indeterminate box beams will
be given in the next section.

EXAMPLE
PROBLEMS

- Example 1 Shear flow distribution,
axial force calculation, and shear center location in a single-cell 2-flange
cantilever beam

To Section IV.3
To Section
IV.1

To Index Page of
Transverse Shear Loading of Closed Sections