Steel Angle Ledger
Steel Angle Ledger
(OP)
Looking to do a project where we need to support new concrete plank onto an existing concrete wall with a steel angle ledger. I have two options in terms of angle position, option #1 toe up and option #2 toe down (see attached).
Both configurations offer some advantages over the other. However, I believe option #1 is better as you can rely on the plank to help reduce the tension load on the anchor. Basically the anchor will only see tension load from dead weight of the plank as once the dry pack/grout is in place the bending loads in the angle can be supported by the plank itself. Is reducing this tension load a valid option with option #1?
Both configurations offer some advantages over the other. However, I believe option #1 is better as you can rely on the plank to help reduce the tension load on the anchor. Basically the anchor will only see tension load from dead weight of the plank as once the dry pack/grout is in place the bending loads in the angle can be supported by the plank itself. Is reducing this tension load a valid option with option #1?






RE: Steel Angle Ledger
RE: Steel Angle Ledger
BA
RE: Steel Angle Ledger
BA, the sketch is rough for the purposes of conveying the problem. In the end, I believe the plank will be welded to the ledger.
RE: Steel Angle Ledger
RE: Steel Angle Ledger
RE: Steel Angle Ledger
It's a pity really, as I like the geometric simplicity of #2. I like that the angle fillet doesn't interfere with the precast and the welds to the plank embed plates seem cleaner.
I don't believe this to be the case. In the final state, the plank and dry pack will rotate away from the wall and thus the dry pack will not really participate. With appropriate welds on the horizontal leg of the support angle you can, however, make an argument that you've moved the shear close to the vertical angle leg and thus eliminated most of the tension from the anchor. And this would apply to both options. I rarely do this though as it requires more attention to detail in the design and construction of both the embed plate and the connecting welds.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Steel Angle Ledger
KootK
Missing from both options is a 2" concrete topping. The plank will be attached to foundation wall on 3 of the 4 sides of the structure (1 side being the existing concrete wall 2 sides being new). The 4th side is the entrance to the garage. So in this instance, for the plank to move, the entire structure would need to move and I don't think that is going to happen (that wasn't obvious in the thread above).
RE: Steel Angle Ledger
RE: Steel Angle Ledger
@Brad: are the groove welds that you mentioned the welds between the horizontal angle leg toe and the plank embed plates in option #1?
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Steel Angle Ledger
In order for the plank to rotate about the support opposite the section the plank would need to move laterally away from the existing wall. Again, I don't think that is going to happen.
RE: Steel Angle Ledger
RE: Steel Angle Ledger
I don't see it. See sketch A below for the rotation that I'm thinking of that would be unaffected by lateral restraint. For sport, I threw in my favorite new construction version and an FBD of the angle model that eliminates/reduces bolt tension. I have to admit, however, that I'm finding Brad805's latest comments pretty persuasive.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.