steel Silo compression ring
steel Silo compression ring
(OP)
I am trying to determine the appropriate allowable compressive stress in a steel silo compression ring.
Gaylord and Gaylord indicate 10 ksi, but note that this could increase to 18 ksi for low frequency usage silos.
Troitsky indicates 10 ksi.
Both of those just used blanket statements with no backup.
I found another source that indicate 12.8 ksi and a fourth that used .5Fy.
The fourth source appears to be the only one that indicated that they were taking Fy into account.
Does anyone have any insight that would be helpful?
Gaylord and Gaylord indicate 10 ksi, but note that this could increase to 18 ksi for low frequency usage silos.
Troitsky indicates 10 ksi.
Both of those just used blanket statements with no backup.
I found another source that indicate 12.8 ksi and a fourth that used .5Fy.
The fourth source appears to be the only one that indicated that they were taking Fy into account.
Does anyone have any insight that would be helpful?






RE: steel Silo compression ring
RE: steel Silo compression ring
RE: steel Silo compression ring
RE: steel Silo compression ring
The compression ring gets its compression from the tension in the conical hopper, but it also gets bending, torsion and "rolling" due to eccentricity of the hopper shell from the centroid of the ring. A compression ring can buckle, so the buckling length enters into the calculation as well.
There have been many failures of silos over the years. The following is a very interesting link to an article written by a firm which has investigated numerous silo failures.
http://
BA
RE: steel Silo compression ring
This section was written by two engineers, including the Chief Structural Engineer, of Chicago Bridge and Iron Company. I think their advice would have been based on a lot of experience.
RE: steel Silo compression ring
RE: steel Silo compression ring
If a compression ring is actually in tension, then it's a tension ring, not a compression ring. It is usually a flat plate or an assembly of elements, not a curved plate.
Gaylord and Gaylord wrote both the Structural Engineering Handbook and also a bin and silo book, so "G&G" can mean two different books.
RE: steel Silo compression ring
RE: steel Silo compression ring
To answer a couple of the questions from above:
1. This is the compression ring where the hopper meets the shell.
2. This silo is containing solids
3. I have Gaylord and Gaylord's Structural Engineering Handbook. I haven't been able to get my hands on their bin and silo book yet.
As Hokie indicated, these books recommend limiting the compressive stress to 10 ksi to minimize deflection and buckling- I just hate magic numbers and was hoping to find out how they got to that number- and just how conservative they are being.
Thanks
RE: steel Silo compression ring
However, when it comes to loading from the flow of solids, I am not as confident that I have addressed all the possible load variations so I would tend to use 10ksi as a extra factor of safety to reflect this. The ref. given by BA indicates that this is a very complicated loading condition and I would certainly be very careful in addressing it. The 10ksi allowable is really a shot in the dark and , in hindsight, may not be a good substitute for a more rigorous analysis.