Reinforcement detailing of Columns from ETABS output

Download the given model of ETABS. Running the analysis. Once analysis is completed, running the Concrete Frame Design.

1. Area of longitudinal reinforcement is obtained from ETABS as below for column 3A and 3B:

2. Area of shear reinforcement is obtained from ETABS as below for column 3A and 3B:

Obtaining the story data from the ETABS as below for detailing the reinforcement details of columns 3A & 3B.

Referring the clause 8.1 of the IS 13920: 2016 for detailing special confining reinforcement.

8.1.a. Where lo is not less than

1. Larger lateral dimension of the member = 650 mm
2. 1/6 of clear span of the member – 1500/6 = 250 mm
3. 450 mm

Hence, adopting lo = 650 mm in both columns 3A & 3B

Highest longitudinal reinforcement required for column 3A is 7027 mm2.

Choosing 10 numbers of 32 mm dia bars as longitudinal reinforcement.

Area of steel provided = 10 x 804.24 = 8042.47 mm2 > 7027 mm2. Hence safe.

Highest longitudinal reinforcement required for column 3B is 5046 mm2.

Choosing 2 numbers of 32 mm dia and 8 numbers of 25 mm dia bars as longitudinal reinforcement.

Area of steel provided = 2 x 804.24 + 8 x 490.87 = 5535.48 mm2 > 5046 mm2. Hence safe.

Further, referring the clause 8.1 of the IS 13920: 2016 for detailing special confining reinforcement.

8.1.b. Spacing of special confining reinforcement shall not less than

1. ¼ of minimum member dimension of the beam column = 450 mm
2. 6 times diameter of the smallest longitudinal reinforcement bars and = 6 x 25 = 150 mm
3. 100 mm

Hence, adopting spacing of links as 100 mm c/c over length = 650 mm in both columns 3A & 3B.

Splicing of longitudinal reinforcement is to be provided over a distance of 41 x dia of bar = 41 x 32 = 1312 mm = 1300 mm with closed links @ spacing of 100 mm c/c in both columns 3A & 3B as shown in the detailing ( within the mid half height of column in that storey).

The details of the reinforcement and section details of column 3A are as below:

The details of the reinforcement and section details of column 3B are as below: