Large shear with continuous 2 span - am I analyzing this right?
Large shear with continuous 2 span - am I analyzing this right?
(OP)
I have a 29' column primarily supporting lateral load at the upper 25'. 1.5' from the base of the column will have steel members and steel plate framing into 3 sides of the column (with welds all around). I'm analyzing this as a continuous two span (beam) and it's coming up with huge shears at the base connection due to the short 1.5' span. I pinned all three supports.
Am I modeling this correctly? It is possible to look at this as just two simply supported members therefore eliminating the large shears I'm getting? Or because it is a continous member it has to be looked at as a two span continuous member?
Any input would be great.
Am I modeling this correctly? It is possible to look at this as just two simply supported members therefore eliminating the large shears I'm getting? Or because it is a continous member it has to be looked at as a two span continuous member?
Any input would be great.






RE: Large shear with continuous 2 span - am I analyzing this right?
To eliminate the extra leverage though, I would consider, if possible, putting a lateral slip connection at the 1.5 foot mark and designing it as a single span member.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Large shear with continuous 2 span - am I analyzing this right?
BA
RE: Large shear with continuous 2 span - am I analyzing this right?
As Mike says, if you can provide a slip connection, do it. You're not modeling anything wrong, it's the geometry. If you can't do that, then consider pinning the column at that location. A typical column splice detail from AISC would qualify as a pin. This will provide axial continuity, but discontinuity for moment which will take care of the shear problem.
RE: Large shear with continuous 2 span - am I analyzing this right?
take moments about the lower support ... Pu*1.5 = P*25 ...
Pl = P-Pu, and (naturally) there's a large moment at teh upper support.
RE: Large shear with continuous 2 span - am I analyzing this right?
No, the column has three supports. One at the base, one at 1.5' from the base, and one at the top (29'). At least that's the way I read it.
RE: Large shear with continuous 2 span - am I analyzing this right?
BA
RE: Large shear with continuous 2 span - am I analyzing this right?
Michael.
Timing has a lot to do with the outcome of a rain dance.