Adding gusset/bracing to shackle hangers...

I added tubing across each set of hangers and added tubing front to rear as well. I also added shocks. Frame cracks have not reappeared since the upgrades. I made everything bolt in so that the belly can be accessed if needed.

The usual method is to weld a piece of 2x2 square tubing from one spring hanger to the other directly across, above the bolt holes in the hanger and close to the frame. This would transfer any stress to the other side when backing to balance the forces of twisting to both hangers instead of just the one. To be honest you may not need to do anything unless you can see some evidence of excessive flexing while backing.

This is part of the fix recommended by Dexter which made my frame on my fifth wheel when the I-beam frame cracked near the spring hangers. I have the Dexter info if you would like to see it-just send me your e-mail in a PM.

It couldn't hurt.
I'd go with the drawing on the left. Add plates on the front and rear of the hangar, as drawn.
Then add another 2 gussets to mount in the middle of the frame. One in front and rear sides of the new plates.
No disassembly of existing hanger. Discard drawing on the right as I'm assuming the trailer frame is an I frame.
Pat
Pat

The usual method is to weld a piece of 2x2 square tubing from one spring hanger to the other directly across, above the bolt holes in the hanger and close to the frame. This would transfer any stress to the other side when backing to balance the forces of twisting to both hangers instead of just the one. To be honest you may not need to do anything unless you can see some evidence of excessive flexing while backing.

From your photo's it appears that they used over sized spring hangers and had to pinch them together to fit your springs inside. I also see that a few of your shackle bolts are not pulled down to the shackle all the way. You might want to check those.

If you do it by your sketch you'll need longer bolts. I don't know how hard they might be to find. Also, you need to take precautions to not blow electronic control boards when welding. I can't see any harm in adding braces but I've never heard of anyone having a problem with factory brackets either.