Reinforcement detailing of Columns from ETABS output

Aim: Reinforcement detailing of Columns from ETABS.

Introduction:

• A column is a vertical structural member intended to transfer a compressive load.
• Columns are the structural elements that transfer the load to foundations and into the ground.
• It resists axial load as well as Lateral loads.
• Circular column should have a minimum of 6 bars
• Rectangular columns must have a minimum of 8 bars (4 at corners and 4 at mid length)
• As per IS456-2000(design code for RCC structures), the minimum c/s area of lomgitudinal steel is 0.8% of gross cross sectional area of column.
• Bars should not be less than 12mm in diameter.

Procedure:

• Open Etabs.
• Open the downloaded file.
• Now Check the errors in Model
• If no error then Analyse the model.
• After analyzing Go to the Concrete Frame Design.
• After finishing the design go to set view option and untick the Beam option.

• Now go to the elevation view about 3.

• Go to Display Design concrete Frame results and select Shear Reinforcement.

3A and 3B Longitudinal Reinforcement 3A and 3B Shear Reinforcement

Column cross sectional & elevation details using autocad software.

• The reinforcement details for the column 3A is given as:
  • Here the maximum longitudinal reinforcement required is 7027 mm^2.
  • Hence, provide 8 no.s of 32mm dia bars and 2 no.s of 20mm dia bars which together contributes an Ast of 7058 mm^2.
  • Now, for shear reinforcement, the maximum reinforcement area required is 720 mm^2
  • Hence, provide 10mm dia bars @ 150mm c/c at zone A and a spacing of 100mm c/c at zone B ( at splicing location and near the beams) which contributes to an Ast of 1570 mm^2 and 2355 mm^2 respectively.

• The reinforcement details for the column 3B is given as:
  • Here the maximum longitudinal reinforcement required is 5046mm^2 .
  • Hence, provide 4 no.s of 32mm dia bars and 6 no.s of 20mm dia bars which together contributes an Ast of 5100 mm^2
  • Now, for shear reinforcement, the maximum reinforcement area required is 720 mm^2.
  • Hence, provide 10mm dia bars @ 150mm c/c at zone A and a spacing of 100mm c/c at zone B ( at splicing location and near the beams), which contributes to an Ast of 1570 mm^2 and 2352 mm^2 respectively.

Shear reinforcement & lapping details as per special confining reinforcement provision of clause 8.1 of IS 13920 - 2016.

Result:

• The given Etabs model has been analysed after checking the model.
• Then concrete frame design has also been carried out hence the reinforcement area required has been obtained.