RAM Concept considers walls above the slab to act as
beams. It appropriately analyzes the influence of these walls on the slab, but
it does not report the wall-beam forces nor does it design the wall-beams.
Design strips and design sections that cross walls ignore both the capacity of
the wall-beam in the cross section and the forces in the wall-beam. Wall-beams
interpret some wall properties differently than walls below the slab:
- Fixed Near = wall has torsional stiffness
- Fixed Far = (ignored)
- Shear Wall = beam has axial stiffness
- Compressible = (ignored)
Note that while the prediction of the bending behavior of
the slab and beam is accurate, the division of shear between the wall and the
slab is not well predicted. For a combined wall-beam / slab section the
proportion of the vertical shear force carried by the slab will be between the
two extremes:
where
| As
| = | cross-sectional area of slab in
section |
| Atotal
| = | cross-sectional area of slab and wall
together |
| Is
| = | moment of inertia of slab |
| Itotal
| = | moment of inertia of slab and wall
together |
