It is important to understand "shear core" before using cross section trimming.

RAM Concept defines the shear core as the parts of the trimmed cross section that include any vertical slices that extend from the top of the cross section to the bottom of the cross section, as shown in the following figure.

RAM Concept bases one-way shear calculations on the entire shear force and shear core. For example, in a T-beam the shear calculations are based on the cross-sectional area of the stem and the flange immediately above the stem.

Cross-sections can have multiple separate cores. For example, in a double-T-beam, the core is the two stems and the flange areas above the two stems. RAM Concept typically considers this core to be the same as a single core with the same (total) width.

Shear core (shaded) for various cross sections

Some odd shaped cross-sections do not have a shear core. In such cases, RAM Concept cannot calculate some capacity values (such as shear capacity).

One cross section with a narrow shear core and one with zero shear core.