Section IV.4

### Section IV.4 Multiple-Cell Multiple-Flange Beams: Symmetric and Unsymmetric Cross Sections

For finding the shear flow distribution and shear center location in two-cell or multiple-cell (i.e., more than 2 cells), multiple-flange beams the same methods demonstrated in section IV.1 can still be used. Keep in mind that such beams are always statically indeterminate, and we must use either the direct method or the shear center method to solve for the shear flow distribution.

However, following the procedure described in section IV.1 does not provide us with sufficient number of equations to solve for all the unknown shear flows. An important fact to remember in these problems is that all the cells will twist the same amount.

This will help us establish sufficient number of equations to solve for the unknown shear flows.

The equation for the angle of twist is the same as the one used before for closed-section beams with constant-shear-flow webs.

EXAMPLE PROBLEMS

• Example 1 Analysis of a two-cell multiple flange box beam

To Section IV.5