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

AIM

• To run the analysis and design the RCC shear wall
• To extract values of the longitudinal steel ratio,boundary element length and shear reinforcement ratio from design results
• To provide the elevation drawings of the reinforcement details of shear wall

INTRODUCTION

ETAB or ETABS they mean the same. Its full form is extended three-dimentional analysis of building system. It is an engineering software product that caters to multi-story building analysis and design. ETABS offers a single user interface to perfom modelling, analysis, design and reporting.There is no limit to the number of modelling windows,model manipulation views and data views.

OBJECTIVES

• To know the design of RC shear wall using ETABS analysis
• To know the basics of RC shear wall reinforcement detailing with respect to primary standards
• To ensure the ductility reinforcement required by IS-13920-2016 been satisfied in reinforcement drawing

PROCEDURE

STEP:1

• Open the attached file in ETABS

STEP:2

• After opening the file,we should be able to see all the shear wall provided at all the floors from the top plan view
• Select the terrace plan view and click apply

• Select the all stories option present at the right bottom corner
• Then select the grid A-11

• After selecting the grid A-11 shear wall at all the floors,right click at the workspace and select the show selected objects only

• To see the elevation view of the showing shear wall at grid A-11
• Select the elevation view tool
• Tab will be opened and from that select the elevation11

• Make sure that the pier label is applied at all the shear walls before
• After that the shear wall can be analyzed and it should be done by clicking Run Analysis

STEP:3

Shear Wall Design

• We have to click on the shear wall design icon
• Now we have to wait till the design completes

• After the completion of shear wall design,to know the other reinforcement member requirements for the shear wall
• we need to select the DISPLAY DESIGN INFORMATION

• After selecting the 'display design info' option the new tab appears, in that we select pier longitudinal reinforcement and click the ok button

• pier Longitudinal reinforcement details will appear

• Then again select 'display design info' option the new tab appears, in that we select pier shear reinforcement ,click the ok button

• Pier shear reinforcement details will appear

• Then again select 'display design info' option the new tab appears, in that we select pier edge/boundary zones width ,click the ok button

• Check the stories and grids
• For that go to Edit story and grid system tab
• From that select modify/show story data

STEP:4

DETAILING GUIDELINES FOR SHEAR WALL:

• Minimum reinforcement of shrinkage and temperature
• ultimate limit state design rebar requirements-----whichever is greater ,should be drawn in RC shear wall detailing
• Ductility rebar requirement

a.Detailing guidelines for shear wall:

classification of shear wall as per IS 13920-2016 clause 10.1.4

hw/Lw = 21000/1500 = 14

hence ,14 is greater thsn 2,so the shearwall design may be of slender wall type

b.Minimum net vertical reinforcement as per IS 13920-2016 table1(3)

taking area from top view

=0.0025+0.01375(300/1500) = 2363mm^2

c.Minimum vertical reinforcement within the boundary element table 1(3)

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

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

d.Minimum horizontal reinforcement in shear wall as per IS 13920-2016 table1(3)

we have formula for value of p is unknomn,

p = 750/(300/1000)=0.0025

we having, hw=21000,Lw=1500

so,

(ph)min = 0.0025+0.5(21/15-2)*0

(ph)min=0.0025(same as 750mm)

e.Minimum diameter of rebar for shear wall as per IS 13920-2016 clause 10.1.8

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

hence, available rebars diameter are 25,32mm

so,using 25mm dia rebar

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

As per the conditions,maximum spacing of confining reinforcement in boundary element will be 150mm

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

Ash = 0.05 sv h fck/fy

where,

sv= 150mm

h=1000mm

substituting the value

Ash= 452mm^2

DRAWINGS:

RESULT

• We have run the analysis and designed the RCC shear walls ( show in the etabs model) for size 300*1500 ar grid A-11 in the structural model
• Also we extracted the values of longitudinal steel ratio, boundary element length and shear reinforcing ratio from the design results
• Also provided cross sectional steel arrangment of the shear wall from its base up to terrace , in compilance with provisions of IS 13920-2016