huangyhg

second order analysis for a cantilevered column
i am trying to understand how to correctly implement second-order analysis, and i am having a difficult time understanding what to do for a simple cantilever column. the column has both an axial load and a lateral load acting at the very top. i think that the first order moment caused by the lateral load is the "mlt" term, but does this mean that there is no "mnt" term for this application? i am also confused on the calculation of the "b2" amplification factor. any insight would be greatly appreciated!
that is correct, there would be no mnt. i believe mnt would be if you had a moment applied at the top of the column (as you would have in a moment frame from gravity loads - not the lateral load portion of the moment at the top).
i don't have my 13th edition manual in front of me (and i don't re
nevermind, i just looked it up online. the equations looks pretty straightforward....
summation pu = the sum of all factored column loads acting on all columns of the story under consideration.
deltaoh is the drift of the story under consideration
summation h=the sum all horizontal forces causing delta oh
l=story height.
the second option loks easier to calculate, but would take longer to come up with the values.
summation pu= same as above
summation pe2= sum of all euler loads for the columns in a story. be sure to keep track of weak axis/strong axis for x and y directions.
i should clarify that you can have mlt from gravity loading if your loading (or the frame geometry) is not symmetrical such that the gravity loading causes sway in the frame.
jscolostate-
if you have software available that can perform a rigorous second order analysis, it would be much easier to simply model it by the direct analysis method. there are several threads in this forum dealing with this, but if you would like, i can give you a brief summary.
but if you choose to not analyze your beam-column by the direct analysis method, structuraleit is right. mnt stands for "no translation".

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