Reinforcement detailing of Columns from ETABS output

Reinforcement detailing of columns in Etabs 2018.

The ETABS file for a G+4 building is provided. Run the analysis and design the RCC Moment Resisting Frame. The following challenge deals specifically with two columns at the following grid intersections.

1. 3A
2. 3B

• Provide details of longitudinal reinforcement for the two columns, from foundation to terrace level. Sketch the column cross sectional & elevation details or draft it using AutoCAD software.
• Show shear reinforcement & lapping details as per special confining reinforcement provision of clause 8.1 of IS 13920 - 2016.

AIM:

In the given Etabs project we have to analyze and redesign the RCC moment resisting frame in two columns at the following grid intersection 3A & 3B from foundation to terrace level by using etabs with reference of IS 13920-2016

INTRODUCTION:

In the modal we provide the details of longitudinal reinforcement of two columns and shown shear reinforcement, lapping details as per special confining zone of clause 8.1 of IS 1920-21016

PROCEDURE: -

• Open the challenge 7 attachment which are provided to us
• After downloading open the Challenge open it in the Etabs 20 software

• Select the 3A and 3B columns from all stories as shown a in below;

• Change the view into Elevation view - 3
• And Run the Analysis

• Now we have to start the column design by selecting the "concrete frame design" a below showing;

• Below showing longitudinal reinforcement of the columns 3A and 3B after run the analysis

• Now we are separately showing longitudinal reinforcement and shear reinforcement of the columns

Longitudinal reinforcement and shear reinforcement and Diagrammatical details of the column at grid 3A from ETABS;

1. Longitudinal reinforcement: -

2. Shear reinforcement: -

NOW WE HAVE TO PROVIDE DEATIL REINFORCEMENT TO THE COLUMN;

1. For GRID 3A -

From Base to first floor the maximum Ast = 7027 mm2

So, we can provide 8 no's of 32 mm diameter bar = 8 x 803.84

= 6430.72 mm2

also, we can provide 2 no's of 20 mm diameter bar = 2 * 314

= 628 mm2

8 no's of 32 mm+2 no's of 20 mm = 6430.72+628

=7058.72 mm2>7027 mm2 ........hence okay

Special confining reinforcement from IS-13920-2016(Clause 8.1)

Lo not less than-

1. Larger column dimension
2. 1/6 of clear span of column
3. 450 mm

Confinement spacing not more than-

1. ¼ of smaller column dimension
2. 6 times of dia of column main bar
3. 100mm

The amount of confinement rebar- .

Ash=169mm2

Diagrammatical Details of column at grid 3A are shown below -

Longitudinal reinforcement and shear reinforcement and Diagrammatical details of the column at grid 3B from ETABS;

1. Longitudinal reinforcement: -

2. Shear reinforcement: -

2) For GRID 3B -

From Base to Terrace floor the maximum Ast = 5046 mm2

So, Provide 8 bars of 25 mm diameter for the column = 8 x 490.87*8

= 3927mm2

Provide 2 bars of 32 mm diameter for the column = 4 x 314.16

= 1607.68mm2

Therefore;

Provide 8 bars of 25 mm diameter for the column + Provide 4 bars of 20 mm diameter for the column =

= 3927 + 1607.68

= 5534 mm2>5046 ...........hence okay

Special confining reinforcement from IS-13920-2016(Clause 8.1)

Lo not less than-

1. Larger column dimension
2. 1/6 of clear span of column
3. 450 mm

Confinement spacing not more than-

1. ¼ of smaller column dimension
2. 6 times of dia of column main bar
3. 100mm

The amount of confinement rebar- .

Ash=169mm2

Diagrammatical Details of 3B Grid are shown below;

Now, Typical Beam column Joint as per special confining reinforcement provision of clause 8.1 of IS 13920 -2016

As per IS 13920 - 2016 at beam column junction: -

• For beam - The spacing from the face of the beam should not be more than 100 mm till 2d
• For Column - The spacing from the face of the column will be lo and should not be more than least lateral dimension, (16)th of clear span or 450 mm

RESULT: -

• The given Etabs model has been analyzed after checking the model.
• Then concrete frame design has also been carried out hence the reinforcement area required has been obtained.
• The longitudinal reinforcement details obtained from the results have been drafted in AutoCAD software.
• Similarly, the shear reinforcement details also have been drafted.