Wayne Whitney wrote:

...if a point load bears on the top plate of a stud wall, does the
stud wall spread out the load by the time it reaches the bottom plate?

How many pounds of point load? What kind of studs, on what centers?

In the scenario I was considering, a header would pick up
two 12' floor joists 16" on center

Like this, viewed in a fixed font like Courier?

| 16" |
floorfloorfloorfloorfloor
j j
o o
i i
s s
t t
headerheaderheaderheaderheader
s s
t t
u u
d d
. .
. .
. .

and one end would be supported by the stud wall.

One end of what? The joists? The header? Is the stud wall
parallel to or perpendicular to (as above) the joists?

As to the specifics of the stud wall, that is flexible. Anyway,
it is not a lot of weight, as 12' x 4' = 48 sq ft,

Where does the 4' come from?

but the end of the header only carries 1/4 of that,
so 12 sq ft @ 50 lb/sqft = 600 lbs.

Where do the 1/4 and 12 square feet come from?

P.S. I'm probably not going to go with this design, but I'm still
interested. It's been fun learning how to size beams.

Sizing beams is easy... W, L, M, f, S, b, d.
Figuring how they share loads can be harder.

Nick