If you turn the C channel by itself so the 2" dimension is vertical and the
1" legs are horizontal, simply support the ends of a 5' piece, and put a 600
lb load at the center to simulate a live load of a 200 lb person jumping up
and down the deflection will be 0.34" at the center and the maximum stress
will be 32.6 ksi which is in the ballpark of the yield strength of A36
steel. Weld that top 1" horizontal leg flat to the bottom of your 1/8"
plate, add the cross piece of channel, and it should be plenty strong
(safety margin at least 5x, I'm too lazy to calculate out the effect of the
plate plus channel). Best would be two channels parallel to each other
spaced apart some distance, with a third channel perpendicular to those
across the center, but that's got to be serious overkill. If you turn the C
channel so the 2" dim is horizontal and the 1" legs are vertical going up to
touch the bottom of the plate and welded there the strength drops by a
factor of 4-ish, so don't do that :-). Ymmv, worth what it cost, yadda
yadda :-). You are on your own for how fast the strength drops with rust.

(I love engineering power tools, www.pwr-tools.com, for quickie stuff like
this; just a satisfied customer.)

-----
Regards,
Carl Ijames
"Jerry Kaidor" wrote in message
...

Hello,

A few years ago, I bought a house. Clearing the jungle in the yard, I
discovered a ratty old shack. Under the ratty old shack was a dug well. I
demolished the shack and made a temporary well cover out of plywood and
4x4's.

Now I want to make a real cover, drop down a solar well pump and actually
use the thing. Irrigating my acre with city water is expensive.

The County well guy has a strange requirement: don't paint the cover!
Huh?
Whatever. Government says "jump", I ask "how high"?

I am planning to fabricate the real cover out of 1/8" steel. It's thick
enough so I won't worry about surface rust, and easy to work. I have a
decent
MIG welder, TIG welder, a small plasma cutter, and a ring roller, and I know
how to use them . I am very comfortable cutting and welding 1/8" stock.

I have poured a substantial foundation around the well with embedded
anchor bolts for the cover. It came out about an inch low when I ran out of
concrete.
I had calculated that the requirement was 25 bags, I had 41 bags on hand.
Go figure.

The well diameter is about 5 feet.

So the current plan ( subject to change ) is:

* Fabricate a flange to drop down onto the foundation bolts. Make it out of
segments of 6" wide 1/8" plate, cut to size with the plasma cutter. Lay the
segments on bricks on the foundation and weld them together to form a 6-foot
diameter ring.

* Use the ring roller to make a 5-foot diameter ring of 1" strap. Weld the
strap to the big flange. That will make up for the short foundation.

* Lay some A-36 "C" channel ( 2 inches wide by 1" high by 1/8" stock )
across
the mouth of the well. Maybe one piece, maybe two pieces side by side.
Maybe put a stiffening piece of 4" steel strap between the two C-channels.
Cut a couple more C-channels and weld them at right angles to the main ones,
forming a large "X". Weld the X to the supporting ring.

* Cut pie-shaped slices of 1/8" thick plate. Cut pump and inspection ports
into two of the slices. Stiffen the ports with steel rings rolled out of 1"
or 3/4" strap.

Lay the slices on top of the "X" and weld them in place. Playing with a
CAD drawing, I see that I can get two slices out of a 4'x4' sheet of steel
with minimal waste.

When all the welding is done, pull out the bricks and drop the cover into
place on the foundation bolts.

When the cover is complete, I will build a "wishing well" gazebo over it
to protect it from the weather. I made enough space on the foundation for a
cute curved brick wall.

Does this sound strong enough?

- Jerry Kaidor