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 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.
INTRODUCTION:

ETABS is an engineering software that is used for multi-story building analysis and design. Modeling tools and templates, code-based load prescriptions, analysis methods and solution techniques, all coordinate with the grid-like geometry unique to this class of structure.

Here we are analysing a given structure and detailed drawing of the shear wall is drawn using AutoCAD.

We provide longitudinal and shear reinforcement according to the results from the ETABs analysing.

PROCEDURE:

Step 1:Open the given file

Step 2:Set it ot the plan view, Set terrace level.

Step 3:Select the shear wall of the grid A-11.

Step 4:Right click and select show selected objects only.

Step 5:Click on Run Anaysis, set the elevation.

Step 6:Click on shear wall design.

1.Select pier longitudinal reinforcement(vertical reinforcement).

Step 7:Click on shear wall design.

2. Select Display Design Info,

Select Pier shear reinforcement(horizontal reinforcement)

Step 8:Click on shear wall design.

3. Select Display Design Info,

Select Pier edge/boundary zone widths.

Step 9:Select story details.

Detailing guideline for Shear wall :

Classification of Shear wall as per IS-13920-2016 clause 10.1.4 : Slender wall. as per IS -13920-2016 CLAUSE 10.1.4.

hw/Lw= 21000/1500 = 14 > 2

1)Minimum net vertical reinforcement as per IS-13920-2016 Table-1 : (iii)

=0.0025 + 0.01375 (thickness of wall/length of wall )

=0.0025 + 0.01375 (300/1500)

It is taken as 2363 mm2.

2)Minimum vertical reinforcement within boundary element Table-1 (iii)

1440 mm2 on left (600mm width boundary element)
1080 mm2 on right (450mm width boundary element)
3)Minimum horizontal reinforcement in shear wall as per IS-13920-2016 Table-1 (ii).

(Ph)min = Ph + 0.5 (hw/Lw - 2) x (Ph - 0.0025)

Ph = 750/(300x1000) = 0.0025, hw = 21000, Lw = 150

(Ph)min = 0.0025 + 0.5 (21/15 - 2) x 0

(Ph)min = 0.0025, which is the same 750 mm2/m.

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

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

Commercial rebar diameter 25 mm shall be adopted

2 additional boundary element bars of 12 mm diameter is provided.

.5)Confining reinforcement spacing for boundary element as per IS-13920-2016 clause 10.4.4

(i) 1/3 of minimum member dimension = 300/3 = 100 mm
(ii) 6 times smallest main rebar = 6x25 = 150 mm
(iii) 150 mm permissible if vertical bars are spaced at maximum 200 mm

maximum spacing of confining reinforcement in boundary element 150 mm.

6)Confining reinforcement within boundary element as per IS-13920-2016 clause 10.4.4

Ash = 0.05 x sv x h x (fck/fy)

sv = 150 mm, h = 1000 mm

Ash = 452 mm2