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-   -   maximum slenderness ratio (http://www.dimcax.com/hust/showthread.php?t=26366)

huangyhg 2009-09-10 01:23 PM

maximum slenderness ratio
 
maximum slenderness ratio
hi,
does anybody use, as a rule of thumb, a maximum slenderness ratio for concrete columns even though structurally a slender column can work?
thanks
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start with kl/r<22 (that is assuming k=1.0 and m1=m2 with single curvature)
since i don't have time, budget or software to do a full-fledged analysis, i keep the slenderness below 100 to avoid this (aci requirement).
if the slenderness ratio is above 100, you have to do a more detailed analysis of the secondary effect.
as a preliminary design, you should use the minimum allowed area of steel to determine the area of column. this way, at the end of the design if you find the column needs more capacity then you can only increase the area of steel to achieve this.
it seemed to me he was asking about avoiding slenderness checks. the op does say that even though a slender column can work, what slenderness ratio do you shoot for. i interpretted that to mean to avoid the slenderness checks altogether.
was that your intention?
unless you have very tall architectural columns carrying little load, kl/r will almost never approach 100. i had a job recently in which it exceeded 100 and a detailed second order analysis was required, but these were architecural columns that were very small in cross-section due to having very little load (and the look the architect was going for).
if these columns had any significant load on them, the section would have needed to be bigger and the slenderness ratio would have come way down.


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