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 (SHOW IN THE ETABS MODEL). THE FOLLOWING CHALLENGE DEALS SPECIFICALLY WITH THE SHEAR WALL OF SIZE 300 X 1500 AT GRID A-11 IN THE STRUCTURAL MODEL

• EXTRACT VALUES OF LONGITUDINAL STEEL RATIO, BOUNDARY ELEMENT LENGTH AND SHEAR REINFORCING RATIO FROM THE DESIGN RESULT
• 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 DRAWING OF THE REINFORCEMENT DETAILS OF THE SHEAR WALL FROM BASE UP TO TERRACE

ANS:

• DESIGN RULE OF ANY REINFORORCED CONCRETE MEMBER:

1. Minimum reinforcement for shrinkage & temperature
2. Ultimate limit state design rebar requirement
3. Ductility rebar requirement
4. Above three point whichever is greater should be drawn in RC shear wall detailing
5. Classification of shear wall as per IS – 13920 – 2016 clause 10.1.4 slender wall hw/Lw = 21000/1500 = 14>2
6. Minimum net vertical reinforcement as per IS – 13920 – 2016 table – 1 (iii) 2363 mm^2 / = 0.0025 + 0.01375 (300/1500)
7. Minimum vertical reinforcement within boundary element table-1 (iii)

1440 mm^2 on left (600mm width boundary element)

1080 mm^2 on right (450mm width boundary element)

• PROCEDURE:

1. First download and open the etabs file

1. Then select the shear wall 11A from the model

1. Then select only selected items show
2. Then run the analysis by simply pressing f5
3. Then analysis will completed

6. Minimum horizontal reinforcement in shear wall as per IS-13920-2016 table- 1 (iii)

(ƿ_h)min = 0.0025 + 0.5(h_w/L_w -2)( ƿ_h-0.0025)

Ƿ_h = 750/(300x1000) = 0.0025

h_w = 21000

L_w = 1500

(ƿ_h)min = 0.0025 + 0.5(21/15-2) x 0

(ƿ_h)min = 0.0025 which is the same 750mm^2/m

7. Maximum diameter of rebar for shear wall as IS-13920-2016 clause 10.1.8

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

Commercial rebar diameter 25mm shall be adopted

8. Confining reinforcement spacing for boundary element as per IS-13920-2016 clause 10.4.4
9. 1/3 of minimum member dimension = 300/3 = 100mm
10. 6 times smallest main rebar = 6 x25 = 150mm

• 150mm permissible if vertical bars are spaced at maximum 200mm

Maximum spacing of confining reinforcement in boundary element 150mm

9. Confining reinforcement within boundary element as per IS-13920-2016 clause 10.4.4

A_sh = 0.05 s_v h f_ck/f_y

S_{v =} 150mm, h = 1000mm

A_sh = 452mm^2

10. Reinforcement details as per following:

• RESULT:

This is how we provided the reinforcement in the shear wall.