Reinforcement detailing of Columns from ETABS output

1.1 Aim of the project- To know the design of RC column using ETABS analysis, the basics of column reinforcement detailing with respect to primary standards using AUTOCAD and to ensure the ductility reinforcement required by IS 13920-2016 satisfied in ETABS design.

1.2 Introduction-

• Plan and 3d elevation of G+4 building with beam size and column size is given below,

• The two columns at the grid intersection 3A and 3B is given below,

2.1 Procedure-

Step-1 – Firstly the ETABS file has been opened and every material properties and load properties has been checked.

Step-2- After verification of material properties and load properties, the model has been analysed by F5 bottom or by directly clicking on run analysis bottom on ETABS.

Step-3- After completion of analysis, the analysed model has been design by clicking on the concrete frame design bottom which designs the longitudinal reinforcement and shear reinforcement for all the load combination of all the members in the model which can be checked by clicking on drop down bottom of concrete frame design and the by clicking on display design info.

Step-4- Design details i.e. flexural details and shear details for all the load combination of every members in the model can be checked by right clicking on the required members and directly the designs can be access.

Step-5 After finding the design details, then the given grids has been done the detailing.

2.2 All the step wise screen shots in analysing and designing the concrete frame structure is given below,

3.1 Results and Discussion

• Detailing rule of reinforcement concrete members
  1. Minimum reinforcement for shrinkage and temperature
  2. Ultimate limit state design rebar reinforcement
  3. Ductility rebar reinforcement

RC beam detailing is chose whichever is greater among above condition 1, 2 and 3.

• Minimum longitudinal reinforcement as per IS 456-2000 clause 26.5.3.1.

A_S= 2340 mm²

• Minimum shear reinforcement or transvers 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 × diameter of bar

• longitudinal reinforcement of column (450×650) at grid intersection 3A

• longitudinal reinforcement of column (450×650) at grid intersection 3B

• Shear reinforcement of column (650×450) at grid intersection 3A

• Shear reinforcement of column (650×450) at grid intersection 3B

• Special confining reinforcement from IS 13290-2016 (clause 8.1)

3.2 Calculation of l₀, which would be the maximum value among following three value i.e. 1, 2, and 3.

1. Larger column dimension= 650mm
2. (1/6)^th of clear span of column

= (1/6) × 3500= 583.33 mm for column of span 4m.

= (1/6) × 2950= 491.67 mm for column of span 3450 mm.

So, l₀ = 650 mm as it is higher value among 1, 2 and 3.

3.3 Calculation of confinement of spacing, which would be the minimum value among following three value i.e. 1, 2, and 3.

1. (1/4)^th of smaller column dimension = (1/4)× 450= 112.5mm
2. 6^th time of diameter of column main bar= 6× 32= 182mm
3. 100mm

Hence the confinement of spacing is 100mm.

3.4 Calculation of amount of confinement rebar,

Ash= 169 mm²

• After getting the value of longitudinal reinforcement and shear reinforcement columns at grid intersection 3A and 3B from ETABS, the detail reinforcement has been drafted using AUTOCAD which is given below,

NOTE-

The results in analysing and designing of the buildings as per the given data by using ETABS i.e. the .edb file named as “Challenge7_EtabsModel” and detailing of reinforcement for grid A and grid 1 which has been drafted in AUDOCAD i.e. dwg file named as “Chng_8_column_REINFORCEMENT” have been uploaded below.