A house builder or engineer will know, you got a few idiots in. Can a
24ft piece of steel be moved in. Even a beam large enough to hold
without a mid support could be even more trouble and cost. You need
supports on both sides while you remove and instal the new one, and good
new footers. If old beam if not rotted leave it in. Jacking that hight
should be done over 2 months but may not be possible as windows and
doors may not work and walls will crack. Even joists settled over time
will split needing sistering of new joists. Ive done a few I would get
3 jacks mid floor set up. And 2 end if those supports are not good. Get
footings poured under the jacks and DIY over months monitoring doors
windows walls, joists , floors etc. How much you go up depends on alot
of things and even now no one knows nor will you till you see the
adverse affects. Jacks for 3, 45$ -150$ depending on how big your load
is. Concrete 6- 8 bags a hole 100$ for 3. Rent a electric demolition
hammer 55- 75$ a day a half day will do it. Labor for digging and
footings 150-500$ You can do it all or just the jacking as you should,
as that takes measurements and alot of time and care.