Reinforcement detailing of Columns from ETABS output

Aim:

To know the design of RC Columns using ETABS analysis.

To know the basics of column reinforcement detailing with respect to primary standards.

To ensure the ductility reinforcement requirement by IS- 13920: 2016 has been satisfied in ETABS.

Given data:

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.

Detailing rule of any concrete member:

If any one of the below conditions is required, then it should be included in RC Column design.

1. Minimum reinforcement for shrinkage and temperature.
2. Ultimate limit state design rebar requirement.
3. Ductility rebar requirement.

• Minimum longitudinal reinforcement as per IS-456: 2000 clause 26.5.3.1, A_S=2340mm².
• 
• Minimum shear (or) transverse reinforcement as per IS 13920:2016 clause 7.4.2- 8mm diameter at 300mm spacing.
• 
• Development length as per IS 456: 2000 clause 26.2.1 L_d =41 x diameter of bar.
• 

Procedure:

• Open the structural plan from previous challenge.
• 
• Click Plan icon and select Terrace level and click apply.
• 
• Save the model.
• 
• Select All stories in the bottom status and select the columns in the grid 3A and 3B
• 
• Right click on the workspace and click Show selected objects only.
• 
• Select 3D view and Run analysis.
• 
• Click Concrete frame design icon.
• 
• Click elevation icon and select 3^rd grid and click ok.
• 
• Select Concrete frame design -> Display design Info ->Shear reinforcement -> apply
• 
• Column has shear plane along 2 directions X and Y. The values of major axis and minor axis are as per the ductility standards.
• 
• To note down the heights of columns and elevation details, Click Edit -> Edit stories and Grid system -> show/ Modify.
• 
• The longitudinal reinforcement of columns (460x650) at the grids 3A and 3B.
• 
• The Shear reinforcement of columns (460x650) at the grids 3A and 3B.
• 
• Special confining reinforcement from IS 13920:2016 clause 8.1:
• 
• 
• 
• So, by above criteria, l₀ = 650mm, confinement spacing =100mm, the amount of confinement rebar= 169mm².
• Longitudinal reinforcement:
• Longitudinal reinforcement for the columns at the grids 3A and 3B are given below.
• 
• 
• Result:
• In 1 link we provide 3 legs of 8mm which will satisfy 150mm².
• At least 2 legs will be provided in l_o length which would come 300mm².
• It satisfies the above calculated amount of confinement rebar, 169mm².
• Hence the result is obtained by the above steps.