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The slenderness ratio is calculated according to clause 10.11.5 in ACI 318-05, see formula below
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luy(z) |
system length (unsupported length) of member about y(z) axis of LCS |
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ky(z) |
effective length factor about y(z) axis of LCS of compression member |
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ry(z) |
radius of gyration of cross section about y(z) axis of LCS of compression member, |
The value ky(z) can be calculated according to clause R10.12.1 in ACI 318-05 , if type of calculation is Code dependent, see chapter "5.4 Member buckling data". The following formulas are then used for calculation effective length factor
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Non-sway member |
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Sway member restrained in both ends |
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Sway member restrained in one end |
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For non-sway member restrained in one end, only value ψ in the end of member which is fixed is taken into account
If the member will be sway or non-sway can be set in dialog Buckling and relative lengths > Buckling data or in dialog Buckling coefficients (member buckling data is defined, user input is selected and kyy(zz) = Code dependent ) via property Swaz zz or Sway zz
If the member will be restrained in both ends or only in one end can be set in dialog Buckling and relative lengths > Buckling data via propertie yy or zz
In the table below are calculated slenderness ratio for sway and non-sway member with restrains in both ends and one end too (member B1 – non-sway column restrained in both ends, B2- non-sway column restrained at foot of the column, member B3 –way column restrained in both ends, B4- sway column restrained at foot of the column ).
if 
if 
