I doubt your 5-2x10 beam is failing. Rather, it appears that it was poorly laminated together. I would NOT recommend jacking the BEAM, but rather “securing” the hangers to the beam AND the beam to the structure (building).
You have several issues: 1) structural adequacy and transfer from hangers to beam, 2) connection of sistered joists together, 3) post to beam connections, 4) post to floor connections
1) The joists that span 10’ and sit on top of the beam is not an issue. However, the joists that span 16’ and sit in a hanger is a problem. The reaction (and thus the load on the hangers) is about 650 lbs. each. That means the hangers need to be rated for such a load and installed properly. Most hangers rated to carry that kind of load have a tab that fits over the top of the beam. If these do not, then they need the bigger diameter “short” nail. Without the correct nail it could allow the hanger to settle (which it appears like it’s doing in the second photo).
You didn’t say, but if the lower floor is uneven, then you need to “re-align” the hangers, not jack the beam. You can do this by removing the hangers one at a time and reinstall level.
2) Because the hanger is fastened to the side of the beam, it needs to transfer the load to all the sistered beams. I’d install a 1/2” bolt through all the joists at 32” o.c. (between the hangers) top and bottom (which will be 16” o.c. between top and bottom bolts). Keep the bolts 2 1/2” clear from the edges, top and bottom.
3) This is an important beam in your house. It’s carrying about 950 lbs. of floor load per foot, which means you have about 4,750 lbs. of load at the posts. Get a connector that’s rated accordingly.
4) Likewise for the footing connection.
The joists and beam are structurally adequate. The beam just needs to be secured together. Jacking the beam will cause significant problems above and should be avoided if possible, unless the floor is uneven because the beam is “tipping”. If that’s the case, other issues apply.
In your original statement, you seem to indicate that there are just floor joists on this beam. However, in one of your responses you seem to indicate that there are 2 load bearing walls on the beam too. If so, those loads are not accounted for in this analysis. If so, please advise.
The Code requires a Live Load (people, furniture, etc.) of 30 lbs. per square foot plus all Dead Loads (joists, subfloor, underlayment, carpet, etc.) Dead load is usually about 10 lbs. per square foot.
So, the Total Load is a minimum of 40 lbs. per square foot.
If your new wood beam has joists that are 10’ long resting on it, you’d have a load of: 10’/2 x 40 psf = 200 lbs. per linear foot. (Half the load will rest on the beam and half will transfer to a wall or other support.)
However, if the new beam has 10’ long joists resting on it from both directions, then you’d have a load of: 10’ x 40 psf = 400 plf.
Therefore, if joists are just spanning one way onto the beam, I’d use a 4x6 spanning 10’ (allowable load is 211 plf), depending on the species and grade. However, if joists are resting on the beam from both directions, I’d use a 4x8 spanning 10’ (allowable load is 400 plf) depending on the species and grade. (I’ve used “select structural” grade for both.)
For both beams, I’d use a 4x4 post and connect it to the beam with a steel connector, like this from Simpson:
https://www.fastenersplus.com/Simpson-EPC4Z-4X-End-Post-Cap-ZMAX-Finish?gclid=CjwKCAjwqqrmBRAAEiwAdpDXtPEhWgfFN3t5VkNWQXQCCTj66l7QkMfB9j2WiAIj2a1ltQrorGAXJxoCTDMQAvD_BwE
Also, I’d make sure the post sits on a footing and is connected to it with a Simpson connector like this one:
https://www.fastenersplus.com/Simpson-ABU44Z-4x4-Adjustable-Post-Base-Zmax-Finish?gclid=CjwKCAjwqqrmBRAAEiwAdpDXtMKhk_lo2NOToXapoUP4b7MPRZad5-csx-D_fpCLj7xPKBsQpgU5zhoCrwgQAvD_BwE
I don’t understand the 12’ span info added at the end.
Best Answer
A multi span joist with intermediate bearing (3+ points of bearing) can clear span more than a simple/single span joist (2 points of bearing.) One span benefits from having the other span connected to it.
Your dropped LVL is called intermediate bearing. It is typically sized to L/360 live load deflection, and the floor tributary is 5/8 of the joist span because of the added load from continuity.
When you flush that LVL, you typically size it to L/480 live load deflection, but you only use 1/2 of the joist span as the floor tributary. Obviously you have to cut the joists, so they can't span as far as joists that are continuous over the LVL.
These small differences mean that sometimes it matters if you flush or drop the beam. Just make sure you check the joist span works as a simple span, and that the LVL deflects less than L/480 live so that you don't reduce the floor's performance.
In my experience, going from dropped to flush with the same size LVL (which is what you're doing) works 90% of the time. You still need to check it though.
Doing the opposite and going from flush to dropped can add 1/8 more floor tributary to it, so it's more likely to fail in moment or shear with the added load.