Analysis & Design of RCC shear walls in the model using ETABS
Answer to the question
Question:
The etabs file for a G+6 building is provided. Run the analysis and design the RCC shear walls (show 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 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 base up to terrace.
Answer:
AIM: Aim to the question is To run the analysis and design the RCC shear walls shown in the etabs model.
INTRODUCTION:
In this question, we need to 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.
PROCEDURE:
STEP-1
- Open the ETABS file
- After the analysis click Concrete frame design
STEP-2
- Need to check there is any failures occurs
- Click Shear wall design tool
- Select Display info and choose PM failure
STEP-3
- Click any wall and check the details
- Here there is no failure occurs all the values of reinforcement ratio is within 4%
STEP-4
Shear Reinforcing
- Go to concrete frame design
- Click Display design info
- Choose Shear reinforcing
STEP-5
Boundary element width
- 1) Go to concrete frame design
- 2) Click Display design info
- 3) Choose Pier edge or boundary zone width
STEP-5
Longitudinal Reinforcement:
- 1) Go to concrete frame design
- 2) Click Display design info
- 3) Choose Pier longitudinal reinforcing
RESULT & CALCULATIONS
Flooor:
te = 300mm
le = 1500mm
Boundary od element =
| 600 |
450 |
| 450 |
300 |
Height of enter wall hw = 10500
clause 10.1.6 (Table wall)
minimum reinforcement in Rc sheare walls when the total height of the wall devided by the length in more than 2if it similar blender wall we need to calculated,
Horizontal min, Reinforcement = Pn min.
Vertical B.E. reinforcement = Pv BE min.
Minimum web reinforcement, Pv web min
Net reinforcement, Pv net min.
So ,
Pn min = 0.025+ 0.5 ()`(hw)/(Lw) -2`(pn-0.025)`
lv be min = 0.0080
lv web= 0.025
lv net = 0.025 + 0.01375 `((tw)/(lw))`
= 0.025 + 0.01375 `((300)/(1500))`
For Longitudinal Reinforcement:
lw = Lw - 2 tw
= 1500- 2(600)
= 300
From ETABS:
The required Revar area, Av = 13128 mm^2
So,
Minimum Vertical Reinforcement lv,
= `(13128)/(C.S. area' of Steel)`
= `(13128)/(1500X300)`
lv = 0.029 >0.0080
From Is 13920,
Ash= 0.05 Sv h `(fck)/(fy)`
Minimum No. of Bar = 8
So Ash = `π/4 d^2`
= `π/4 8^2`
Ash= 50.24 `mm^2`
Now, 50.24 = 0.05 x 100x h `((25)/(500))`
50.24 = 0.025h
h = 200.96
use `ϕ` = 25mm
= `((13128)/((π/4)*25^2))`
= `((13128)/(490.625))`
= 28 bar
For Shear= Reinforcement
For 2 legged 16 mm Dia bar
Ash =`π/4 d^2`
= `π/4 16^2`
= 803.84 `mm^2`
Provide 6 No. of 12 mm in web.