On Jun 22, 1:50*pm, dpb wrote:
Oh, OK, I went back to your drawing and sketched it out on paper w/
dimensions. *I see what he did was to automatically place his columns
under the upstairs walls to get the direct support transmitted
vertically. *That's kewl...but what strikes me is that he doesn't need
additional beam to transmit that (locally distributed) point load; the
existing beam is (apprently) doing that fine w/o crushing so it will
continue to do so.

Yes, moving the columns under the ones from the ground floor was
automatically considered. Turns out that the required footing is much
larger than I had expected, so I have to tear down a whole lot more
basement for this solution. This is why I'm looking for alternatives.

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?

It almost sounds like he's discounting the existing beam entirely owing,
I suppose, to the point I didn't catch early on of it being a 12-ft run
on 8-ft supports. *I'm not going to second-guess the guy but I'd wonder
if it really is needed to actually get that full U section under the
existing beam at the outside end.

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.

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.


To do any calculation would require knowing all the loads assumed,
live/dead/additional code-required for the jurisdiction, etc. *They
ought to be on the design documents if you have access to those but if
all you've contracted for is a design, that may not be part of the deal.

Yes, the codes are on the drawing, but not the assumed loads. I can
get him to add these numbers I suppose.

I understand all the complexities involved here, so I'm not looking
for formal advice: that's why the engineer is working for me.

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!


As others noted, it would be possible to rig up ways to get it there but
it does just seem pretty stout for the application from afar and w/o
actually doing any real numerics, of course...

--

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