Civil Engineering - RCC Structures Design - Discussion

A short steel column is one whose slenderness ratio does not exceed 50; an intermediate length steel column has a slenderness ratio ranging from about 50 to 200, and are dominated by the strength limit of the material, while a long steel column may be assumed to have a slenderness ratio greater than 200.

For RCC Column, i) When the ratio of the effective length to its least lateral dimension is less than or equal to 12 it is called as short column. . Why this is important? - Long columns under compression can fail via both bucklings (bending sideways) as well as crushing.

As per IS 456 and SP16 (clause 3.4 of compression members) if Slenderness ratio leff/LLD is more than 12 it is a long column. For steel structures, the Slenderness ratio is Leff/r min and its limiting value is 180.

S. N ratio for short column <41 or =41.

And for long column >41.

Yes, that means Slenderness limit should not exceed 60. Beyond that limited, a column can't be considered.

According to IS 456:2000 (Clause no.25.3.1).

The unsupported length between end restraints shall not exceed 60 times the least lateral dimension of a column.

L/b <= 3 pedestal.
3<L/b<=12 short column.
12<L/b<=60 long column.
L/b >= 60 redesign.
As per IS456: 2000.

According to is 456 2000, for long column λ should be less than 60.

IS 456 2000 clause 25.3.1 explained about unsupported length, not for short/long column.

I think option C 40 is correct.

Let me clear all ur doubts,

L/least dimension <3=pedestal,
3-12 = short column,
12-60= intermediate col,
>60.
Also;
L/radius of gyration<30= short col,
30-120=intermediate col,
>120.