Deep Beam "Arch Action" Theory for Steel Rods
Deep Beam "Arch Action" Theory for Steel Rods
(OP)
I have a 10" steel rod spanning 10" with a uniform load.
If I think about this problem as I would a deep concrete beam utilizing deep beam theory - as a compression arch, I am fine with the combession stresses.
I also evaluated it as a bending member and found my stresses were close to the allowables.
Just to confirm that I was being conservative, I looked this up in my trusty Roark's book (4th Ed page 131). Here, my "arch action" idea is out the door, in addition, to simple bending. Roark indicates there is a penalty in short beam. For a L/d ratio of 1 for my case, I have to decrease my allowable stress (or increase my applied moment) by a factor of 2.725!! Ouch. Any help interpreting this would be greatly appreciated.
If I think about this problem as I would a deep concrete beam utilizing deep beam theory - as a compression arch, I am fine with the combession stresses.
I also evaluated it as a bending member and found my stresses were close to the allowables.
Just to confirm that I was being conservative, I looked this up in my trusty Roark's book (4th Ed page 131). Here, my "arch action" idea is out the door, in addition, to simple bending. Roark indicates there is a penalty in short beam. For a L/d ratio of 1 for my case, I have to decrease my allowable stress (or increase my applied moment) by a factor of 2.725!! Ouch. Any help interpreting this would be greatly appreciated.






RE: Deep Beam "Arch Action" Theory for Steel Rods
However, I guess that your section will fail in PLAIN SHEAR before you have to take any pain of going further with the bending analysis. If the span is short, check the shear first before other things.
RE: Deep Beam "Arch Action" Theory for Steel Rods
FEA may be of help where contact produces a different load distribution or yielding redistributes the load somehow, otherwise you're on to a loser.
Incidentally, in Roark's 6th ed. the table is referred to on page 203.
RE: Deep Beam "Arch Action" Theory for Steel Rods