Phil wrote:
On Jun 22, 1:50 pm, dpb wrote:
....

It would seem the only real function the additional structural member
has to do is to handle the distributed load across the longer gap which
shouldn't be that great it would seem.

The additional member here is the steel piece?

Yes, see below for more on that...

....

I see w/ that location of the two columns you do have roughly the 16-ft
open space; I'm just surprised since the bulk of the loading is on the
ends instead of distributed it requires so much heft. What's the
dimension on the U he's given, including thicknesses?

So, the proposed steel piece is a U: its legs are 10 inches high, the
base is 9 inches wide and would run along 40 inches of the beam. It's
1/4 inch thick.

Since the beam is made of 3 sections of 12 feet, this piece is there
only to support the connection of 2 of those sections. The steel piece
would cover 20 inches on both sides of the split.

In my mind, the proposed columns (at 4.5 feet and 20 feet) are doing
all the work really since they're directly below the ones on the
ground floor.

Indeed, that's where I was confused before...I had misunderstood and
thought this U was the full-length beam replacement and were trying to
figure out how to get it in place on one end. I couldn't figure out
how, since the main load was, as you say being carried by the columns
one needed anything anyways near that stout as the intermediate beam
between them. That it's a gusset plate I can go with at the dimensions.

But, that leaves me w/ the problem of not understanding what's the issue
in the installation I think.

I asked him to look into another solution that has only one column at
16 feet (instead of 2: one at 4 and 20). The reason is that this 16
feet span would better suit what's around it: more specifically, the
staircase. As mentioned above, a single column would have less impact
due to the size of the required footing.

....

In your mind, a 16 feet span with steel support around the split at 12
feet, a proper column at 16 feet, w/ proper footing *could* handle
this? Again, not looking for formal advice, here, I just want to steer
my engineer in the proper direction. They don't come cheap!

No, I don't think that would work; what I was envisioning was a full
length side plate of (say) 1/2" x 10" bolted thru the existing beam to
handle the longer span w/ the upstairs load handled by the columns.

I thought your original proposal was to replace the existing beam in its
entirety and my suggestion was to leave it in place and rather than put
something underneath it over the existing column to trim the joists and
rehang them leaving the vertical primary support on the column.

I think there's still some talking past each other owing to each having
a vision but not a common set of drawings/concepts...

....

Yeah. Seems like a much larger job than I really expected...

Always is when get an engineer involved...

Altho I commend you for getting somebody to actually look at the
situation given the nontrivial nature of the loading distributions and
particularly that discontinuous beam that complicates things.

Good luck; knowing the guy didn't try to fit in a full-length U to
bridge the gap and claim it had a stress problem makes me feel much
better about his doings...I believe it for the 1/4"T short section to
hold the end moments; I wasn't so sure when presumed it was much heavier
material and full length. vbg

--