Combination of steel grades in one section
Combination of steel grades in one section
(OP)
Hello everyone!
I wonder if it's possible to compose a section made of wide flange column in 65 ksi with welded cover plates in 50 ksi? How to calculate its compressive resistance when there are 2 grades within one section? Any other things that I should be aware of when designing such a section?
I wonder if it's possible to compose a section made of wide flange column in 65 ksi with welded cover plates in 50 ksi? How to calculate its compressive resistance when there are 2 grades within one section? Any other things that I should be aware of when designing such a section?






RE: Combination of steel grades in one section
It is easy to see how this works when designing elastically, but becomes a bit more complicated when trying to address plastic design.
I wouldn't do this if I could avoid it, and I would be looking for specialist support from the Steel Solutions Centre, HERA, or other industry expertise. Contact the appropriate industry resource for your area of practice; They are frenquently only too happy to help, and nearly always for free or nearly-free!
RE: Combination of steel grades in one section
the more detailed approach is to check both materials. it's all straiing at the same rate, just part A is limited to 50ksi and part B 65ksi. i think you need to be careful is selecting loadcases to make sure you're loading up the weaker material as much as possible.
another approach maybe to allow/permit the 50ksi to yield and hope that the 65ksi material with restrain it and carry the load required.
another day in paradise, or is paradise one day closer ?
RE: Combination of steel grades in one section
RE: Combination of steel grades in one section
1) Your wide flange section starts going plastic first at locations where Fy is effectively reduced due to residual stress patterns. Your plates, on the other hand, don't really have any residual stresses.
2) If the wide flange is an existing column, there will be locked in compressive stresses in it unless you're able to jack the supported structure to relieve the stress in the column.
Is this a new member or a reinforcement for an existing column? I have a handy cheat if it's an existing column.
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Combination of steel grades in one section
RE: Combination of steel grades in one section
RE: Combination of steel grades in one section
@Formi: two practical points of interest:
1) When your welds cool it will wreak havoc on the cross section residual stress patterns. As a result, there's little point getting too fancy analytically unless you're desperate for capacity or there're a thousand of these things. Just use the lower Fy.
2) Keep an eye on how the compressive load gets delivered to the combined section. If the load isn't applied uniformly to all the parts, you need to quickly get an appropriate share of it out of the wide flange and into the plates at either end of the member (heavy local welding). I only point this out because I've seen it missed a few times in the past.
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Combination of steel grades in one section
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Combination of steel grades in one section
I was just showing my two interns (one male, one female) "The Honeymooners". They couldn't believe the jokes, nor believe that the audience was laughing as Ralph threatens to hit Alice. We have come a long way, and most all of it very good... So far that the youth today don't even believe you when you mention the "old norms".
RE: Combination of steel grades in one section
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: Combination of steel grades in one section
RE: Combination of steel grades in one section
2) maybe the audience laught is canned, perhaps emphasising that this is meant to be taken as a joke ?
3) so many things we did, said, thought "back in the day" are so inappropriate now, but back then we didn't have anything like "Sandy Hook" (let me emphasise, no disrespect intended)
another day in paradise, or is paradise one day closer ?