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

Q1).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 :

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.

To model and analyze the G+6 residential building from the given architectural drawings using the ETABS 2018.

INTRODUCTION:

• Shear wall is a vertical element of a system that is designed to resist in plane lateral forces,wind and seismic loads.
• By using the IS 13920-2016 code books to use the designing of the shear wall.

PROCEDURE:

• First open ETAB software.
• Download the attachment given.
• open the Download file in E-tabs.

• Go to plan view.
• and select terrace view.
• and we can see all the floor levels.

• in challange they asked at grid A-11 in the structural model.
• select A-11 in structural mode and select the object
• just right click on the page and go to selcted object.

• Go to elevation and selct grid at 11.

• Go to dispaly option
• and select other assignments.
• labels has appeared.
• remove the label option.
• after that click on run analysis
• and Analysis has been completed and we can see deflections in the menu bar.
• click on shear wall design.

• Go to design dispaly info
• Drop down the box.
• Click on pier shear reinforcing.

• Go to design dispaly info
• Drop down the box.
• Click on pier edze boundary zone widths

• On left hand side max boundary width shall be taken as 650.
• On Right hand side max boundary width shall be taken as 450.
• Go to edit option
• select edit boundary option and check the floor heights.

Vertical ,Horizontal Reinforcement & Boundary element widths of shear wall at Grid-11A frOm E-Tabs (300x1500).

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

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.

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)

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.

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.

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

• 1/3 of minimum member dimension = 300/3 = 100 mm
• 6 times smallest main rebar = 6x25 = 150 mm
• 150 mm permissible if vertical bars are spaced at maximum 200 mm
• maximum spacing of confining reinforcement in boundary element 150 mm.

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.

RESULT:

• After getting all details i drawn the reinforcement of shear wall details by using the auto cad.

• The elevation drawings of reinforcement details of the shear wall from base to terrace has also been drafted.