Partial Moment release
Partial Moment release
(OP)
Hi all, with all these Structural analysis program we use now a days, there is this option of Partial Moment release.
How does one determine the amount of Partial moment to be released? How does one detail a n% moment release connection? My guess is that you assume a partial moment release, then run the analysis after running the analysis you get the forces on that joint and detail it to the accommodate the corresponding forces.
Is my thinking correct? or is there some kind of literature to determine the amount of fixity on a connection?
How does one determine the amount of Partial moment to be released? How does one detail a n% moment release connection? My guess is that you assume a partial moment release, then run the analysis after running the analysis you get the forces on that joint and detail it to the accommodate the corresponding forces.
Is my thinking correct? or is there some kind of literature to determine the amount of fixity on a connection?






RE: Partial Moment release
Base connections I use 0.1*4*E*I/h for pinned and 0.9*4*E*I/h for fixed connections at service conditions.
RE: Partial Moment release
I am interested in how you derived the .1*4*E*I/L equation. This is an equation I often used for pinned foundation/column connections. I know how it was derived on my end, just interested in your end.
RE: Partial Moment release
RE: Partial Moment release
Thank you.
RE: Partial Moment release
It's no trick to get the answers when you have all the data. The trick is to get the answers when you only have half the data and half that is wrong and you don't know which half - LORD KELVIN
RE: Partial Moment release
How did you derived yours?
RE: Partial Moment release
RE: Partial Moment release
For a nominally pinned base:
Where a column is nominally pin-connected to a foundation that is designed assuming that the base moment is zero, the base should be assumed to be pinned when using elastic global analysis to calculate the moments and forces in the frame under ULS loading.
The stiffness of the base may be assumed to be equal to the following proportion of the column stiffness:
• 10% when checking frame stability or determining in-plane effective lengths
• 20% when calculating deflections under serviceability loads
RE: Partial Moment release
RE: Partial Moment release
The paper also brings about clear distinction between moment redistribution coefficients and partial fixity / release......which I am posting here.......
"Within the designing practice there has been some misunderstanding between the moment redistribution coefficient and the partial restriction coefficient. The first is related to moment redistribution, which is caused by cracking in concrete and by yielding of longitudinal reinforcement in the support region, and possesses values limited by the Brazilian Code (ABNT NBR 6118) [2] for linear analyses with redistribution. The latter is not directly related to the type of structural analysis (linear, linear with redistribution, plastic, non-linear), but rather with the most realistic representation
of the conditions of connection between beam and column, in other words, the condition between the fixed and pinned condition. This misunderstanding has become evident from the utilization of commercialized computer systems that allow reductions in negative beam moments."