# Civil Engineering - RCC Structures Design - Discussion

Discussion Forum : RCC Structures Design - Section 1 (Q.No. 4)
4.
The minimum number of main steel bars provided in R.C.C.
rectangular columns is 4
circular columns is 6
octagonal columns is 8
all the above.
Explanation:
No answer description is available. Let's discuss.
Discussion:
23 comments Page 1 of 3.

Qammar Qureshi said:   9 years ago
Min. 4 bars in rectangular/square column and min. 6 bars in circular shape column.

The bar shall not be less than 12mm. The nominal cover shall any case not be less than 40mm.

In our site they provided 40mm cover. Min. Distance b/w individual bars -the dia of larger bar -5mm more.

Nominal max. Size of coarse aggregate.

Shambhoo Kant Jha said:   7 years ago
Minimum diameter for longitudinal bars are 12 mm. It is circular as for given volume, surface area is maximum. Hence more surface area for bond with concrete. In circular, it is 6 bars as it can be compared with hexagonal and 1 bar supposed in each corner for proper placing of lateral ties.

Kanhaiya lal said:   1 decade ago
In Column reversal of bending moment may be occurred, hence, to column are reinforced on both faces. To fulfill the reversal condition of BM minimum no of bars in rectangular is taken as 4, in circular 6 and in octagon 8.

Sameer Sopori said:   5 years ago
@Kiran.

For circular column you can not use 4 bars, For Circular column, you need minimum 6 bar.

And for Rectangular shape of the column, you can use 4 bars minimum.

Shubham Arbat said:   5 years ago
The minimum vertical space of the main reinforcement in RCC beam is the diameter of the larger bar or two-third the nominal maximum size of coarse aggregate.
(1)

Samba said:   9 years ago
India 4 & 5 bars used the column spacing can more than 300 mm so the column concrete will be out side in column. Next the strength will be reduce.

Mohammed said:   8 years ago
Why always the number of steel bar are in even number?

Not in odd number like 5 bars 7 bars.

While we can but the extra bars in the tension zone.
(1)

In column there is a buckling moment due to the up coming load so at each corner there should be a longitudinal main steel bar is provided.

Surajit biswas said:   6 months ago
Can we provide an unequal number of bars (eg- 7 nos, 9 nos, 11 nos, 13nos) in a column? if not why? Please explain to me.

Anuj said:   7 years ago
How many number of minimum main bars provided in a RCC beam?

(a) 2Nos
(b) 3Nos
(c) 4Nos
(d) 6Nos