Web compression buckling
Web compression buckling
(OP)
I'm currently working on a bolted flange plate moment connection for a single story parking garage. I'm just out of college so I've been cutting my teeth with this connection; it's the first time I've had extensive experience with any real connection design, actually. We were originally were utilizing IMF's, which was some serious teeth cutting, but have since reverted to our standard R=3 criteria. I've gotten to the last step of creating my BFP excel spreadsheet, in which I check the need for stiffeners or doubler plates. Thanks to Design Guide 13, I have a good grasp on what's physically going on.
I have a question about the web compression buckling limit state however. At many of our connections, we have between 200-300 k-ft of moment coming in from one side, with sometimes <100 k-ft coming in the other side. As far as I understand, the difference in compression flange forces is made up through web panel shear. What "P" load should I be checking versus the design strength of the web? Conservatively, I realize I could use the larger flange force. Just wondering what your opinions were on the matter. I was surprised I could not find any information on the internet, I assume that in most cases you have different strength flange forces opposing one another?
Thanks,
Ed
I have a question about the web compression buckling limit state however. At many of our connections, we have between 200-300 k-ft of moment coming in from one side, with sometimes <100 k-ft coming in the other side. As far as I understand, the difference in compression flange forces is made up through web panel shear. What "P" load should I be checking versus the design strength of the web? Conservatively, I realize I could use the larger flange force. Just wondering what your opinions were on the matter. I was surprised I could not find any information on the internet, I assume that in most cases you have different strength flange forces opposing one another?
Thanks,
Ed






RE: Web compression buckling
RE: Web compression buckling
RE: Web compression buckling
That being said, I have always used the higher of the two flange forces. I don't mind being conservative. I'm in seismic country, so I'm pre-disposed into thinking that we're going to want continuity plate stiffeners anyway.
RE: Web compression buckling
RE: Web compression buckling
While I know it *can* work given the right loads, I'm not a huge fan of the load path involved in a W section to W section 90 degree moment connection without stiffeners.
RE: Web compression buckling
-Ed
RE: Web compression buckling
From what I have seen 99% of the time engineers require continuity plates in instances like this. I have only seen one engineer on a recent project even considered these forces when he designed his building.... and he increased his column size to eliminate the need for reinforcing at these connections.