Moment release(s) define
Moment release(s) define
(OP)
I am a mechanical engineer, trying to use a simple piece of structural analysis soft. I got stuck in defining the MOMENT RELEASES for my frame:
- six columns in two parallel rows of three each, having all fixed bottom support;
- one beam is running on top of each row of the three columns. The beams' ends are hanging in cantilever beyond the first and the last column top;
- running @ 90ยบ about the previous 2 beams, and resting on top of them, I have 8 other equal spaced beams. These beams' ends also hang beyond their supporting beams.
The whole assembly is welded.
All loads are linear:
- vertical down, on the whole length of each of the upper 8 beams.
- horizontal on the first row of 3 columns, parallel to the upper 8 beams.
My model doesn't work and the area I have doubts about is the definition of Moment Releases, where the manual doesn't explain anything.
I need help (Please understand I am a novice in this field).
Thank you.
- six columns in two parallel rows of three each, having all fixed bottom support;
- one beam is running on top of each row of the three columns. The beams' ends are hanging in cantilever beyond the first and the last column top;
- running @ 90ยบ about the previous 2 beams, and resting on top of them, I have 8 other equal spaced beams. These beams' ends also hang beyond their supporting beams.
The whole assembly is welded.
All loads are linear:
- vertical down, on the whole length of each of the upper 8 beams.
- horizontal on the first row of 3 columns, parallel to the upper 8 beams.
My model doesn't work and the area I have doubts about is the definition of Moment Releases, where the manual doesn't explain anything.
I need help (Please understand I am a novice in this field).
Thank you.





RE: Moment release(s) define
and explain why your model did not work?
RE: Moment release(s) define
I was under the impression I must release of moments the end of the beams hanging beyond the support columns (cantilever). I figured it myself in the mean time, based upon a lot of trial and error and a couple of short nights.
Anyway, thanks again!
RE: Moment release(s) define
Also, the moments do not need to be released at the ends of the cantilevered beam because they are zero anyway. The location of the releases, on the other hand, should be the column/beam connections. Unless you have a moment connection in which you weld the top and bottom flanges to the column flanges, and stiffen the column web, then it is appropriate to release the moments at the column/beam connections. Having said that, if you release the moments at the column/beam connection and change the column base to pinned, then you need some kind of lateral bracing between the column and beams. I usually use 3'-0" (horiz) x 3'-0" (vert) knee braces bolted to gusset plates which are welded to the underside of the beam and the side of the column (45 degrees).
I know I probably confused you even more, but please respond if you have any questions.
Hope this helps,
Mike
RE: Moment release(s) define
RE: Moment release(s) define
My columns are welded to a heavy channel imbedded in the concrete foundation (J hooks and all).
I have gussets to take the wind loads.
The whole construction is welded.
Am I wrong considering all connections fixed?
With regards to Moment Release I figured it out and the analysis shows it right.
RE: Moment release(s) define
RE: Moment release(s) define
I have everything welded directly, with gussets on top, between column and beam. The welds will have a full penetration.
Thanks again,
RE: Moment release(s) define
David R. Dearth, P.E.
Applied Analysis & Technology