Civil Engineering - RCC Structures Design - Discussion

If :
SR < 3 ----> Pedestal.
3 < SR < 12 ----> Short column.
12 < SR < 60 ----> Long column.

According to IS 456.

Short column - Slenderness Ratio <= 12.
Long Column - Slenderness Ratio > 12.

40 is the correct answer.

I believe 12 is the limit for the effective length of a column to its least lateral dimension which is not the slenderness ratio.

However, the limit for the slenderness ratio is 50 and above to be a long column as the slenderness ratio is the ratio of effective length to its least radius of gyration.

According to me, It should be 12 or 40. Anyone, explain the right answer.

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.

I/r is slenderness ration and it should be =<40 / this is for Steel ! Remember.

THIS IS FOR YOUR INFORMATION ,
Short RCC Column =<12.
Long RCC Column >12.
Short Steel column, =<50.
Intermediate Steel Column >40 & <200.
Long Steel Column >200.

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.

There is two solution guys,

1) if Le/d>15 long column.
Le/d<15 short column.
where Le=total length of column and d=width.

2) Other method is to find out radius of gyration K= sqrt(I/A) where I=moment of inertia and A= Area.
Le/k>50 than its long column.
Le/k<50 than its short column.

An R.C.C. column is treated as long as its slenderness ratio is greater than 50.