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 the special confining reinforcement provision of clause 8.1 of IS 13920 - 2016.

Ans:

• Aim:-
  • In the given G+4 ETABS model, the needs to be analyzed & have to design the RCC resisting frames i.e. 3A & 3B only.
  • The reinforcement detailing for the two respective columns needs to be provided from the foundation level to the terrace level using Autocad.
  • The shear reinforcement & lapping detailing need to be provided as per clause 8.1 of IS 13920-2016.

• Open the downloaded ETABS file:-
  • 
• Check The Model:-
  • 
  • 
• Click on Analysis.
  • 
• Select the column intersection from bottom to terrace by clicking all stories in the plan & select the "show selected object only" option.
  • 
• The orientation of the column can be visualized.
  • 
• Click on the concrete frame design button.
  • 
• Go to the drop-down menu of concrete frame design button--> display design info -->Shear Reinforcement --> OK
  • 
  • The same magnitude of minimum & maximum amount of reinforcement represents that, the requirement is minimum for the frames.
• Storey heights of the column
  • 

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

  

  • Here lo is the length up to which the special confining reinforcement should be provided.
  • Requirements for lo as per the clause are

    • Lo not less than-

      • Larger column dimension = 650mm

      • 1/6 of the clear span of the column = 1/6 * 3000 = 500mm

      • 450 mm

    • So lo is =650mm

    • Confinement spacing not more than

      • ¼ of smaller column dimension = 1/4 * 450 = 113 mm

      • 6 times of dia of column main bar = 6 * 20 = 120 mm ( considering 20 mm)

      • 100mm
    • So consider spacing = 100 mm

    • The amount of confinement rebar-.

      

      • =169 mm2

for 3A

Longitudinal reinforcement requirement = 7027 mm2

Provide = 10 - 32dia bar

Reinforcement Detailing for 3A

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• 

For 3B

Longitudinal reinforcement requirement = 5046 mm2

Provide = 8 - 25dia bar + 2 - 32- dia bar

Reinforcement Detailing for 3B

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• 

Additional confining reinforcement of 8mm @ 100mm c/c provided.

After lo distance from joints of 650mm 8mm @ 200mm c/c provided.

At special confining zone 8mm @ 100mm c/c provided.