Reinforcement detailing of Columns from ETABS output

Challange 8:Reinforcement detailing of Columns from ETABS output

Reinforcement detailing of columns in Etabs 2016.

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

AIM:Providing Reinforcement detailing of columns in Etabs 2016.

Procedure:

The G+4 Building is already provided in the previous challange that is 7 so take the same file in etab 2016.

1.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.

Following Procedure is as follows

Step-1:

• Open the file and unlock it
• Check the loads acting on it in the load pattern.
• Further analyse the model to check is there any errors,
• If no errors found then just select Concrete frame design option
• As shown below,

Step-2:

• Select the option as Elevation and select 3A and 3B Elevation.
• And Press left button of mouse and select show only selected beam
• hence it is easy to see.
• Now select the longitudinal reinforcement and design the required amount of rebars.

Step-3:

• By observing the given data of longitudinal reinforcement.
• Provide as possible no of reinforcement required.
• In 3A the Column size was 450mmx650mm
• Hence it required 6939mm2 reinforcement hence provide 12no. of 25 dia bars and 4no. of 20mm dia bars as shown.
• The above detail is from GF to Third floor
• There after the rebars changes to 8no. of 20mm dia and 8no. of 16mm dia bars upto the terrace as shown below.

Step-3:

• In 3B the Column size was 450mmx650mm
• Hence it required 4918mm2 reinforcement hence provide 16no. of 20 dia bars as shown.
• The above detail is from GF to Third floor
• There after the rebars changes to 16no. of 16mm dia upto the terrace as shown below.

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

For Shear Reinforcement just change the option as show shear reinforcement then it shows as shown below

• Hence there is a excel sheet is created wich calculate the no. of Shear reinforcement required
• in which is calculated by formula Ast provided=(1000*no. of legs*ast of stirrup)/Spacing of Stirrup
• Any how in the sismic design evers bar is connected with stirrups and hooks as shown below,

Hence stirrups are provide as 6 legs in the x direction and 4 legs stirrup in the Y @ 150mm c/c as shown Below,

Lapping details as per special confining reinforcement provision of clause 8.1 of IS 13920 - 2016.

Solution,

8.1 Flexural yielding is likely in beams during strong earthquake shaking and in columns when the shaking intensity exceeds the expected intensity of earthquake shaking This special confining reinforcement shall,

1. be provided over a length 1, from the face of the joint towards mid-span of beams and mid heights of columns, on either side of the joint; where /is not less than
2. larger lateral dimension of the member at the section where yielding occurs,
3. 1/6 of clear span of the member
4. 450 mm.
7. have a spacing not more than,

1) 1/4 of minimum member dimension of the in beam or column

2) 6 times diameter of the smallest the longitudinal reinforcement bars; and

3)100 mm link.

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