So I am a relatively new inspector and structural is my area of least experience.
I have a home with a structural wood beam in the basement which is being supported by the foundation wall on both ends and by two steel jacks intermediately spaced between the two ends.
My first question is: Are adjustable steel jack posts allowed for permanent installation? I didn’t think that they were, but not sure.
Secondly, this beam is in 3 sections. One break in the board is directly on top of one of the jacks. To me, this just doesn’t seem like it could possibly be correct from a physics perspective lol but I don’t know the hard and fast rules. The other break in the beam is farther away from the other jack, about 24-30 inches. Are support beams allowed to not be continuous? If so, what is the approved method for joining them?
Also noted was the sistered beams only being adjoined to each other laterally with nails. Should the individual beams not be sistered together with lag bolts such as ledger boards and such?
well for one, thats really not a beam its just some crappy 2x12 slightly nailed together.
it is okay to use 2x12’s triple stacked with seams at least 6 feet away from eachother, but when constructing this, they need about 300 nails nails holding each 2x12 together. here is looks like they only nailed the seam. Not correct at all.
for the post, that is a temporary type screw jack. not meant to be permanent.
as if the beam was doing its job, it would not need a post.
also whats holding it up at the ends? should be triple 2x4 studs under and full studs on both sides.
if it is held up in the walls, and nailed properly throughout the with good 3 1/2" nails or screws both sides. then you should be able to remove the post.
For beams where the load comes down evenly on top of the beam, such as drop beams or beams directly under bearing walls, the nailing pattern is not all that critical. All you need are enough nails to hold the layers together and keep them from twisting.
There is nothing wrong with built up beams nailed together, they been used for residential for years.
Beam pockets are an acceptable procedure for built up beam supports, but should have 1/2" space on 3 sides to prevent moisture damage.
I saw the bowing too and initially thought it may be a structural issue, but there actually is blocking about 2 feet over on the other side of some ductwork. It is staggered and runs between each joist. I think this was just some warped lumber at install. There are several straight joists, but also several bowed ones as well.
The damaged corner of the joist and split, I attributed to nails being toe-nailed too close to the corner of the joist into the top plate of that beam assembly.
Midspan blocking is important. Prevents rotation and movement.
Flooring sag between joists over time as fasteners extrude and eventually squeak.
Required with planking.
A while back I finally broke down and DM’d Larry for the definition of WAFI. I knew the term was not a “pat on the back” but I could not find the words to fill the acronym.
Generally, permanent steel columns will be at least 3" in diameter and not the telescopic type.
Nailed-together built up beams have been very common in some areas (S. California) in the past and the fact that these nails are hand-driven instead of gun-driven testifies to their age. This is not great quality construction compared to modern requirements but actually typical for a certain time frame (during which I was a young framer). 3 nails every 16" as shown here was standard. At that time, architects and engineers had no issue with this method.
As far as the forces that act on spliced framing members Here’s an image from Architectural Graphic Standards:
will turn on for you. 
