For the average $300.00 consultation fee, i would get the advise from a licensed structural engineer.

PE time.

From what you are saying you have a post at 5', 10', 15' & 20'. You want to remove the 2 center post so you have one 5' from the end of each wall. So you want your beam to span 15'? Or do you just one on each end close to the wall & span nearly the entire 25' width? I would say you have 2 choices which depends on the wall heigth. If you have enough room you could put a steel I beam or glulam under the existing beam & span the entire length if you can put a big enough beam in there. Other choice would be to add a flitch plate on each side of the existing beam then cover them with a 1x wrap or 2x wrap, then take out post & wrap the bottom for a finished look. Wherever you buy the gluelam or steel should have some engineering charts that show what loads they can carry. Of course you could hire a consulting engineer that tells you the same thing the charts will, however with an engineer you can get their stamp to guarantee it will hold up to the load. Pick your poison.

Al

Without a load calculation anyone sizing the new beam is just guessing.

The actual beam selection is usually the simple part.
Determining the loads that must be supported to size the beam is what you pay the PE for.

Save the money. Size the beam yourself. If you make a mistake, what's the worst that could happen?

"If you make a mistake, what's the worst that could happen?"

Ummmm... The beam fails and part of the house collapses?

I think Worthy was being facetious...

Odds are that you need to have this approved for code anyway. They will want an engineers signoff for you to be approved. I usually like to go it alone but I agree with the others, this is money well spent.

I'm convinced to bite the bullet and hire someone. I will post back. It could be a while as I have some insulation (posting in garage forum) and electrical work to do first. I appreciate the advice!

Thought this pic of a small building collapse here early yesterday morning might be instructive.

Building collapse: No injuries as 12 tenants in six 2nd and 3rd floor apartments scramble to safety.

The building was undergoing renovations, including opening up space in the first floor bar and other renovations in the basement. No official word on the cause of the collapse. I've got some ideas!

Niiiice. The contractor says he will put plates on the sides, bolt through the 6X10 beam, add two supports at the end, sitting on a footing (which is by code larger than I'd like, around 30x30"), then remove the poles. Hopefully any collapse will happen immediately if it's going to happen....

"which is by code larger than I'd like, around 30x30""

Without an actual load calculation he better put in a larger footing.

If you go looking at beam tables you will not find any for large span steel or even wood beams that do not require a load value to be computed.

The actual sizing of beams ONCE THE LOAD IS KNOWN is pretty simple.
Computing the load is always the issue.
This is a perfect example of GOGO (Garbage In, Garbage Out).
Make a mistake in the load calculation and the beam will be sized incorrectly, and regretfully the most common error is to UNDERSIZE by missing loads.

Just as an example, to size a door header in a two story house requires accounting for the second floor loads above the header, and the roof loads since they are transfered to the wall also.
The load values are done at the design values of 30 PSF live + 10 PSF dead for the second floor, while the roof load includes the roof itself AND the snow loads and sometimes even wind loads, pitch corrections may also be required.

garoj said: "The contractor says he will put plates on the sides, bolt through the 6X10 beam, add two supports at the end, sitting on a footing.."
How did this guy come to this solution?
How thick are the flitch plates?
How many poles are being removed?
Is this beam continuous, or is it spliced over one of the poles that will be removed?
Ron

With the plan of flitch plating, it's still a matter of load calculating as brickeye stated and if the plates are done wrong w/o the proper sized plates/ bolts coinciding w/ the load calcs, they will be risky at best.

Flitch plates ONLY work if they are sandwiched between wood to provide the required lateral stiffness to resist buckling of the plate.
If you want them on the surface you are going to need someone to calculate the required buckling forces and use much thicker plates than a normal flitch beam.

Like brickeye said, the flitch plate needs lateral bracing at the compression side. This can also be provided by thru-bolting near the top of the plate a required spacing. The type of person you want doing this is someone who has fond memories of their early 20's staying up late doing problem sets, thereby acing their structural design courses. If you're relying on anyone else, your relying on someone who is merely guessing. There's more to it than just eyeballing this. A structural engineer will calculate loads according to code (with an infusion of experience and judgement), come up with different options, calculate stresses, deflections, requirements for prevention of lateral-torsional buckling of the compression side of flexural elements (as brickeye says), look at soil types, look at all possible failure modes of a footing (bearing capacity, settlement, internal strength)...and on and on depending on the situation. Shortcuts can be hazardous to your health.

There is a reason that there are no 'per se' flitch designs in the building code.
There are also very few steel beam 'per se' designs also.

There are just way to many things that can go wrong , either immediately or latter (like when a heavy snow overloads the beam, or a wind storm).
We have a pretty good record in this country of not having houses fall down on top of the occupants.

You are proposing a major structural change.
Removing supports increases the load on the remaining ones.
The old end supports for the beam may not be adequate for the increased loads.
Unlike wood construction, steel beams and masonry are far less forgiving of overload.
Nails bend, wood sags.
Steel fasteners often fail in fracture with little warning, and masonry does about the same thing.