Analysis & Design of RCC shear walls in the model using ETABS

AIM -

The etabs file for a G+6 building is provided. Run the analysis and design the RCC shear walls (shown in the etabs model). The following challenge deals specifically with the shear wall of size 300x1500 at grid A-11 in the structural model.

• Extract values of longitudinal steel ratio, boundary element length, and shear reinforcing ratio from the design results.
• Provide cross-sectional steel arrangement of the shear wall from its base up to the terrace, in compliance with provisions of IS 13920 – 2016. AutoCAD application can be used for this exercise. Alternatively, it can be drawn by hand as well.
• Provide elevation drawings of the reinforcement details of the shear wall from the base up to the terrace.

ANS - Opening an attached model in the Etab software - 

opening a plan view - 

opening a plan view of the terrace and open and selecting a shear wall. and open only selected object.

opening an elevation of 11 grid

 

PIER LABEL / ASSIGNMENT CHECK  - 

Click on the set display option after that other assignment. after that check labels and click ok. it shows the pier labels are provided or not.

pier assignment is complete for all the shear wall.

Run the Analysis - 

for running the analysis click on the play symbol which is situated at the top of the ribbon. after that analysis process is started. 

analysis value is shown on the status bar it means over analysis has completed.

longitudinal Reinforcing Area - 

to check the shear design click on the shear wall design and after that analysis has been started.

after analyzing the result it shows the required longitudinal reinforcement area of the wall.

check shear Reinforcing - 

to check the shear reinforcement of the shear wall click on the shear wall drop-down list and after that select a shear reinforcement from the display design info. to shear reinforcement for the wall we called as the horizontal reinforcement.

Boundary zone width -

To check boundary zone width select the same as a dropdown list near the shear wall design. and select boundary zone width from the display design info.

consider boundary zone width according to the left and right sides of the wall.

all longitudanal, shear ,  and boundary zone widths taking from grid 11-A.

Checking Elevation of the building  - 

to checking the Elvation of the building click on the edit tab and after that select edit building storey and modified the storey after that it shows the elevation of the storey which is storey data. it helps to determine the height of the wall.

 Detailed guide line for shear wall - 

1. Minimum reinforcement for shrinkage and temprature.

2. Ultimate limit state design rebar requirement.

3. ductility rebarrequirement 

taking greater value for RCC shear wall detailing.

 

 from IS 456-2000 taking all three value from etab and taking the greater value for shear wall design.

 1. Classification of shear wall as per is 13920 -2016 CLAUSE 10.1.4

Slender wall `h_w/l_w` = 2100/1500 = 14>2

2. Minimum net vertical reinforcement as per IS  13920 -2016 table (1)

2363 mm^2

= 0.0025+0.01375 (300/1500)

3. Minimum vertical Reinforcement within boundary elemenet table (1)

1440 mm^2 on left  

1080 mm^2 on right

 3. MInimum Reinforcement in shear wall as per IS 13920-2016 table (1)`p`

`p_h = 0.0025+0.5(h_w/l_w-2)(p_h-0.0025)`

`p_h` = 750/(300*1000) = 0.0025

`h_w = 21000`

`l_w = 1500`

`(p_h) _min = 0.0025 +0.5+ (21/15-2)*0`

`(p_h) _min =0.0025`which is the same 750mm^2

in Etab there is shown all value in display design info button. 

Maximum diameter of rebar for shear wall as per IS Code 13920-2016 clause 10.1.8

1/10th of wall thickness = 300/10 = 30mm

commercial ribar diameter 25mm shall be adopted.  

 confining reinforcement for boundary element as per IS Code 13920 -2016

1. 1/3 minimum member dimension = 300/3 = 100mm

2. 6 times smallest main ribar 6*25 = 150mm

3. 150 mm  permissible if vertical bars are spaced  at a maximum 200

 maximum spacing for confining element reinforcement in boundary element 150mm

Confining  reinforcement with in boundary elements as per is 13920-2016

 `A_sh = 0.05 S_vh*fck/fy`

S_v = 150mm

h = 1000 mm 

ash = 452 mm^2

Detailing of reinforcement of shear wall - 

After calculation all over value  shows the detailing by using Autocad software. 

 

ELEVATION OF SHEAR WALL -