Wall Supported on Elevated Concrete Slab

Part of the flexibility of designing energy efficient concrete homes is to not have to have walls directly above each other. Most often the determining factor will be the shear strength of the slab to support the wall above.

The question is how does a concentrated load such as a wall spread out to the supporting slab. For simplicity, consider a wall erected on a one way slab that's supported on its edge by a continuous wall. Here's an example:

I'm assuming from common sense that tributaries are usually 45 degree angles. The red triangle becomes a shear distribution, maximized on the wall centerline and tapering to zero at the 45 degree ends of the triangle. The height of the triangle at each point along its base becomes the portion of the shear at that point.

Is this correct?

It's interesting I've found no references to this situation.