HSS tube column (LED sign) with a 3" diameter hole for electrical - torsional issues
HSS tube column (LED sign) with a 3" diameter hole for electrical - torsional issues
(OP)
I am designing an LED sign on HSS tube columns (similar to what you see in front of schools). ASCE 7 says you need an offset for wind forces equal to .2 times the sign width and the extra torsion created gives me problems because the column needs a 3" diameter hole for electrical purposes. I have quite a few books that show me ways of calculating the torsional stress for an open section member and it's not looking good stress wise for this size column that I want to use... But this is also assuming the entire member is open sectioned and not just at the one location. Do I have any method to calculate the benefit of the rest of the member not being open? I.e. stresses will go around the hole (preferably a reference that I can look into), similar to allowable hole sizes in LVLs and the like. Any other ideas to look into? The reason I am searching so much is because other designs I have seen are VERY similar and nothing special was done around the openings, so I felt I missed something but cannot find anything regarding holes in steel members.






RE: HSS tube column (LED sign) with a 3" diameter hole for electrical - torsional issues
RE: HSS tube column (LED sign) with a 3" diameter hole for electrical - torsional issues
RE: HSS tube column (LED sign) with a 3" diameter hole for electrical - torsional issues
There's no need to get into open section torsion here TNich. The intact section either side of the hole will restrain warping at the hole. Saint Venant torsion will do so long as nothing buckles or fractures due to stress raisers.
Some relevant information in Tubular Steel Structures by Troitsky.
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: HSS tube column (LED sign) with a 3" diameter hole for electrical - torsional issues