12 etabs shear wall design manual UBC 97

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Design Manual

1997 UBC

Computers and Structures, Inc.

ã Copyright Computers and Structures, Inc., 1978-2000 The CSI Logo is a registered trademark of Computers and Structures, Inc ETABS is a registered trademark of Computers and Structures, Inc Windows is a registered trademark of Microsoft Corporation.

The computer program ETABS and all associated documentation are proprietary andcopyrighted products Worldwide rights of ownership rest with Computers andStructures, Inc Unlicensed use of the program or reproduction of the documentation inany form, without prior written authorization from Computers and Structures, Inc., isexplicitly prohibited

Further information and copies of this documentation may be obtained from:

Computers and Structures, Inc

1995 University AvenueBerkeley, California 94704 USA

Phone: (510) 845-2177FAX: (510) 845-4096e-mail: info@csiberkeley.com (for general questions)e-mail: support@csiberkeley.com (for technical support questions)

web: www.csiberkeley.com

CONSIDERABLE TIME, EFFORT AND EXPENSE HAVE GONE INTO THEDEVELOPMENT AND DOCUMENTATION OF ETABS THE PROGRAM HASBEEN THOROUGHLY TESTED AND USED IN USING THE PROGRAM,HOWEVER, THE USER ACCEPTS AND UNDERSTANDS THAT NO WARRANTY

IS EXPRESSED OR IMPLIED BY THE DEVELOPERS OR THE DISTRIBUTORS

ON THE ACCURACY OR THE RELIABILITY OF THE PROGRAM

THE USER MUST EXPLICITLY UNDERSTAND THE ASSUMPTIONS OF THEPROGRAM AND MUST INDEPENDENTLY VERIFY THE RESULTS

The Table of Contents for this manual consists of a chapter listfollowed by an expanded table of contents The chapter list de-votes one line to each chapter It shows you the chapter number(if applicable), chapter title and the pages that the chapter covers.Subheadings are provided in the chapter list section to help giveyou a sense of how this manual is divided into several differentparts

Following the chapter list is the expanded table of contents Hereall section headers and subsection headers are listed along withtheir associated page numbers for each chapter in the manual

When searching through the manual for a particular chapter, thehighlighted tabs at the edge of each page may help you locate thechapter more quickly

If you are new to ETABS we suggest that you read Chapters 1through 10 and then use the rest of the manual as a referenceguide on an as-needed basis

then use the

rest of the

man-ual as a

refer-ence guide on

an as-needed

basis.

Shear Wall Design Manual Chapter List

Contents

N A Chapter List i to iii

N A Expanded Table of Contents v to xi

Notation and Introduction

N A Notation Notation-1 to Notation-8

1 Introduction 1-1 to 1-5

Information on How to Design Shear Walls

2 Shear Wall Design Process 2-1 to 2-10

3 Design Menu Commands for Shear Wall Design 3-1 to 3-5

4 Interactive Shear Wall Design and Review 4-1 to 4-18

C Background Information for Shear Wall Design

5 General Design Information 5-1 to 5-9

6 Wall Pier Design Sections 6-1 to 6-6

7 Wall Spandrel Design Sections 7-1 to 7-4

8 1997 UBC Shear Wall Design Preferences 8-1 to 8-4

9 1997 UBC Shear Wall Design Overwrites 9-1 to 9-14

10 1997 UBC Design Load Combinations 10-1 to 10-6

Shear Wall Design Algorithms

11 1997 UBC Wall Pier Boundary Elements 11-1 to 11-6

12 1997 UBC Wall Pier Flexural Design 12-1 to 12-18

13 1997 UBC Wall Pier Shear Design 13-1 to 13-4

14 1997 UBC Spandrel Flexural Design 14-1 to 14-10

15 1997 UBC Spandrel Shear Design 15-1 to 15-5

Shear Wall Design Output

16 Overview of Shear Wall Output 16-1 to 16-2

17 Output Data Plotted Directly on the Model 17-1 to 17-9

18 Printed Design Input Data 18-1 to 18-9

19 Printed Design Output Data 19-1 to 19-27

C Shear Wall Design Manual - Expanded Contents

NOTATION

CHAPTER 1: INTRODUCTION

Overview 1-1Wall Pier Design 1-2Wall Spandrel Design 1-3Organization of Manual 1-4Other Reference Information 1-4ETABS Help 1-4

Readme.txt File 1-4Recommended Initial Reading 1-5

CHAPTER 2: SHEAR WALL DESIGN PROCESS

Typical Design Process for 2D Piers with Concentrated Reinforcing 2-2Typical Design Process for 2D Piers with Uniform Reinforcing 2-4Typical Design Process for 3D Piers 2-7

CHAPTER 3: DESIGN MENU COMMANDS FOR SHEAR WALL DESIGN

Select Design Combo 3-1View/Revise Pier Overwrites 3-2View/Revise Spandrel Overwrites 3-2Define Pier Sections for Checking 3-3Assign Pier Sections for Checking 3-3Start Design/Check of Structure 3-3Interactive Wall Design 3-4

Display Design Info 3-4Reset All Pier/Spandrel Overwrites 3-4

Delete Wall Design Results 3-4

CHAPTER 4: INTERACTIVE SHEAR WALL DESIGN AND REVIEW

General 4-1Interactive Pier Design and Review 4-2Design of a Simplified Section 4-2General Identification Data 4-2Flexural Design Data 4-3Tension Design 4-3Compression Design 4-4Shear Design Data 4-4Boundary Element Check Data 4-5Design of a Section Designer Section 4-6General Identification Data 4-6Flexural Design Data 4-7Shear Design Data 4-8Boundary Element Check Data 4-8Check of a Section Designer Section 4-9General Identification Data 4-10Flexural Design Data 4-10Shear Design Data 4-11Boundary Element Check Data 4-11Combos Button 4-12

Overwrites Button 4-13Section Top and Section Bot Buttons 4-13Interactive Spandrel Design and Review 4-14General Identification Data 4-14

Flexural Design Data 4-14Top Steel 4-14

C Bottom Steel 4-15

Shear Design Data 4-16Design Data for all Spandrels 4-16Additional Design Data for Seismic Spandrels Only 4-17Combos Button 4-17

Overwrites Button 4-18

CHAPTER 5: GENERAL DESIGN INFORMATION

Defining Piers and Spandrels 5-1Analysis Sections versus Design Sections 5-2Units 5-3

Design Station Locations 5-4Design Load Combinations 5-5Wall Meshing and Gravity Loading 5-5Using Frame Elements to Model Spandrels 5-8

CHAPTER 6: WALL PIER DESIGN SECTIONS

General 6-1Simplified Pier Design Dimensions and Properties 6-2Design Dimensions 6-2

How ETABS Calculates the Default Dimensions 6-3Material Properties 6-4

Section Designer Pier Effective Section for Shear 6-5

CHAPTER 7: WALL SPANDREL DESIGN SECTIONS

Wall Spandrel Design Dimensions 7-1Default Design Dimensions 7-3Default Design Material Property 7-4

CHAPTER 8: 1997 UBC SHEAR WALL DESIGN PREFERENCES

General 8-1Shear Wall Preferences 8-2

CHAPTER 9: 1997 UBC SHEAR WALL DESIGN OVERWRITES

General 9-1Pier Design Overwrites 9-2

LL Reduction Factor 9-8

EQ Factor 9-9User-Defined Edge Members 9-10Spandrel Design Overwrites 9-10Making Changes in the Overwrites Dialog Box 9-13

CHAPTER 10: 1997 UBC DESIGN LOAD COMBINATIONS

Default Design Load Combinations 10-1Dead Load Component 10-2Live Load Component 10-3Wind Load Component 10-3Earthquake Load Component 10-3Design Load Combinations that Include a Response Spectrum 10-4Design Load Combinations that Include Time History Results 10-5Design Load Combinations that Include Static Nonlinear Results 10-6

CHAPTER 11: 1997 UBC WALL PIER BOUNDARY ELEMENTS

Details of Check for Boundary Element Requirements 11-1Example 11-5

CHAPTER 12: 1997 UBC WALL PIER FLEXURAL DESIGN

Overview 12-1

C Designing a Simplified Pier Section 12-1

Design Condition 1 12-3Design Condition 2 12-6Design Condition 3 12-6Checking a Section Designer Pier Section 12-7Interaction Surface 12-7

General 12-7Formulation of the Interaction Surface 12-8Details of the Strain Compatibility Analysis 12-12Wall Pier Demand/Capacity Ratio 12-15

Designing a Section Designer Pier Section 12-17

CHAPTER 13: 1997 UBC WALL PIER SHEAR DESIGN

General 13-1Determine the Concrete Shear Capacity 13-2Determine the Required Shear Reinforcing 13-3Seismic and Nonseismic Piers 13-3Additional Requirements for Seismic Piers 13-3

CHAPTER 14: 1997 UBC SPANDREL FLEXURAL DESIGN

General 14-1Determining the Maximum Factored Moments 14-2Determine the Required Flexural Reinforcing 14-2Rectangular Beam Flexural Reinforcing 14-3Tension Reinforcing Only Required 14-4Tension and Compression Reinforcing Required 14-4T-Beam Flexural Reinforcing 14-6

Tension Reinforcing Only Required 14-8Tension and Compression Reinforcing Required 14-9

CHAPTER 15: 1997 UBC SPANDREL SHEAR DESIGN

General 15-1Determine the Concrete Shear Capacity 15-2Determine the Required Shear Reinforcing 15-3Seismic and Nonseismic Spandrels 15-3Seismic Spandrels Only 15-5

CHAPTER 16: OVERVIEW OF SHEAR WALL OUTPUT

General 16-1

CHAPTER 17: OUTPUT DATA PLOTTED DIRECTLY ON THE MODEL

Overview 17-1Design Input 17-2Material 17-2Thickness 17-3Pier Length and Spandrel Depth 17-4Section Designer Pier Sections 17-5Design Output 17-5

Simplified Pier Longitudinal Reinforcing 17-5Simplified Pier Edge Members 17-5

Section Designer Pier Reinforcing Ratios 17-6Section Designer Pier Demand/Capacity Ratios 17-6Spandrel Longitudinal Reinforcing 17-7

Shear Reinforcing 17-7Spandrel Diagonal Shear Reinforcing 17-8Pier Boundary Zones 17-8

CHAPTER 18: PRINTED DESIGN INPUT DATA

Preferences 18-1

C Flags and Factors 18-1

Rebar Units 18-2Simplified Pier Reinforcing Ratio Limits 18-2Interaction Surface Data 18-3

Input Summary 18-3Pier Location Data 18-3Pier Basic Overwrite Data 18-4Pier Geometry Data (Simplified Section) 18-5Pier Geometry Data (Section Designer Section) 18-6Spandrel Location Data 18-7

Spandrel Basic Overwrite Data 18-8Spandrel Geometry Data 18-8

CHAPTER 19: PRINTED DESIGN OUTPUT DATA

Output Summary 19-1Simplified Pier Section Design 19-1Section Designer Pier Section Design 19-2Section Designer Pier Section Check 19-4Spandrel Design 19-5

Required Reinforcing Steel 19-5Detailed Output Data 19-6

Simplified Pier Section Design 19-6Location Data 19-6

Flags and Factors 19-7Material and Geometry Data 19-8Flexural Design Data 19-8Tension Design 19-8Compression Design 19-9Shear Design Data 19-10

Boundary Element Check Data 19-10Additional Overwrite Information 19-11Section Designer Pier Section Design 19-12Location Data 19-12

Flags and Factors 19-12Material and Geometry Data 19-13Flexural Design Data 19-14Shear Design Data 19-15Boundary Element Check Data 19-16Additional Overwrite Information 19-17Section Designer Pier Section Check 19-17Location Data 19-17

Flags and Factors 19-18Material and Geometry Data 19-18Flexural Design Data 19-19Shear Design Data 19-20Boundary Element Check Data 19-20Additional Overwrite Information 19-21Spandrel Design 19-22

Location Data 19-22Flags and Factors 19-23Material and Geometry Data 19-23Flexural Design Data - Top Steel 19-24Flexural Design Data - Bottom Steel 19-25Shear Design Data 19-25

Additional Shear Design Data for Seismic Spandrels 19-26Additional Overwrite Information 19-27

INDEX

1997 UBC Notation

Following is the notation used in this design manual As much aspossible, the notation used in this manual is the same as that inthe 1997 UBC

Acv = Net area of a wall pier bounded by the length of

the wall pier, Lp, and the web thickness, tp,inches2

Ag = Gross area of a wall pier edge member, inches2

Ah-min = Minimum required area of distributed horizontal

reinforcing steel required for shear in a wallspandrel, inches2 / in

As = Area of reinforcing steel, inches2

Asc = Area of reinforcing steel required for

compres-sion in a pier edge member, or, the required area

of tension steel required to balance the sion steel force in a wall spandrel, inches2

compres-N Asc-max = Maximum area of compression reinforcing steel

in a pier edge member, inches2

Asf = The required area of tension reinforcing steel for

balancing the concrete compression force in theextruding portion of the concrete flange of a T-beam, inches2

Ast = Area of reinforcing steel required for tension in a

pier edge member, inches2

Ast-max = Maximum area of tension reinforcing steel in a

pier edge member, inches2

Av = Area of reinforcing steel required for shear,

inches2 / in

Avd = Area of diagonal shear reinforcement in a

cou-pling beam, inches2

Av-min = Minimum required area of distributed vertical

reinforcing steel required for shear in a wallspandrel, inches2 / in

Asw = The required area of tension reinforcing steel for

balancing the concrete compression force in arectangular concrete beam, or for balancing theconcrete compression force in the concrete web

of a T-beam, inches2.A's = Area of compression reinforcing steel in a span-

drel, inches2

B1, B2 = Length of a concrete edge member in a wall with

uniform thickness, inches

Cc = Concrete compression force in a wall pier or

spandrel, pounds

Cf = Concrete compression force in the extruding

por-tion of a T-beam flange, pounds

Cs = Compression force in wall pier or spandrel

rein-forcing steel, pounds

Cw = Concrete compression force in the web of a

T-beam, pounds

D/C = Demand/Capacity ratio as measured on an

inter-action curve for a wall pier, unitless

DB1 = Length of a user-defined wall pier edge member,

inches This can be different on the left and rightsides of the pier, and it also can be different at thetop and the bottom of the pier See Figure 6-1

DB2 = Width of a user-defined wall pier edge member,

inches This can be different on the left and rightsides of the pier, and it also can be different at thetop and the bottom of the pier See Figure 6-1

DL = Dead load

E = The earthquake load on a structure See the

sec-tion titled "Earthquake Load Component" inChapter 10

Es = Modulus of elasticity of reinforcing steel, psi

IP-max = The maximum ratio of reinforcing considered in

the design of a pier with a Section Designer tion, unitless

sec-IP-min = The minimum ratio of reinforcing considered in

the design of a pier with a Section Designer tion, unitless

sec-LBZ = Horizontal length of the boundary zone at each

end of a wall pier, inches

Lp = Horizontal length of wall pier, inches This can

be different at the top and the bottom of the pier

Ls = Horizontal length of wall spandrel, inches

LL = Live load

Mn = Nominal bending strength, pound-inches

N Mu = Factored bending moment at a design section,

pound-inches

Muc = In a wall spandrel with compression reinforcing,

the factored bending moment at a design sectionresisted by the couple between the concrete incompression and the tension steel, pound-inches

Muf = In a wall spandrel with a T-beam section and

compression reinforcing, the factored bendingmoment at a design section resisted by the couplebetween the concrete in compression in the ex-truding portion of the flange and the tension steel,pound-inches

Mus = In a wall spandrel with compression reinforcing,

the factored bending moment at a design sectionresisted by the couple between the compressionsteel and the tension steel, pound-inches

Muw = In a wall spandrel with a T-beam section and

compression reinforcing, the factored bendingmoment at a design section resisted by the couplebetween the concrete in compression in the weband the tension steel, pound-inches

OC = On a wall pier interaction curve the "distance"

from the origin to the capacity associated with thepoint considered

OL = On a wall pier interaction curve the "distance"

from the origin to the point considered

Pb = The axial force in a wall pier at a balanced strain

condition, pounds

Pleft = Equivalent axial force in the left edge member of

a wall pier used for design, pounds This may bedifferent at the top and the bottom of the wallpier

Pmax = Limit on the maximum compressive design

strength specified by the 1997 UBC, pounds

PmaxFactor = Factor used to reduce the allowable

maxi-mum compressive design strength, unitless.The 1997 UBC specifies this factor to be0.80 You can revise this factor in the pref-erences

Pn = Nominal axial strength, pounds

PO = Nominal axial load strength of a wall pier,

pounds

Poc = The maximum compression force a wall pier can

carry with strength reduction factors set equal toone, pounds

Pot = The maximum tension force a wall pier can carry

with strength reduction factors set equal to one,pounds

Pright = Equivalent axial force in the right edge member

of a wall pier used for design, pounds This may

be different at the top and the bottom of the wallpier

Pu = Factored axial force at a design section, pounds

PCmax = Maximum ratio of compression steel in an edge

member of a wall pier, unitless

PTmax = Maximum ratio of tension steel in an edge

mem-ber of a wall pier, unitless

RLW = Shear strength reduction factor as specified in the

concrete material properties, unitless This tion factor applies to light weight concrete It isequal to 1 for normal weight concrete

reduc-RLL = Reduced live load

Ts = Tension force in wall pier reinforcing steel,

pounds

Vc = The portion of the shear force carried by the

con-crete, pounds

N Vn = Nominal shear strength, pounds.

Vs = The portion of the shear force in a spandrel

car-ried by the shear reinforcing steel, pounds

Vu = Factored shear force at a design section, pounds

WL = Wind load

a = Depth of the wall pier or spandrel compression

block, inches

ab = Depth of the compression block in a wall

span-drel for balanced strain conditions, inches

a1 = Depth of the compression block in the web of a

T-beam, inches

bs = Width of the compression flange in a T-beam,

inches This can be different on the left and rightend of the T-beam

c = Distance from the extreme compression fiber of

the wall pier or spandrel to the neutral axis,inches

cb = Distance from the extreme compression fiber of a

spandrel to the neutral axis for balanced strainconditions, inches

dr-bot = Distance from bottom of spandrel beam to

cen-troid of the bottom reinforcing steel, inches Thiscan be different on the left and right end of thespandrel

dr-top = Distance from top of spandrel beam to centroid of

the top reinforcing steel, inches This can be ferent on the left and right end of the spandrel

dif-ds = Depth of the compression flange in a T-beam,

inches This can be different on the left and rightend of the T-beam

dspandrel = Depth of spandrel beam minus cover to centroid

of reinforcing, inches

fy = Yield strength of steel reinforcing, psi This value

is used for flexural and axial design calculations

fys = Yield strength of steel reinforcing, psi This value

is used for shear design calculations

f'c = Concrete compressive strength, psi

f's = Stress in compression steel of a wall spandrel,

psi

hs = Height of a wall spandrel, inches This can be

dif-ferent on the left and right end of the spandrel

pmax = Maximum ratio of reinforcing steel in a wall pier

with a Section Designer section that is designed(not checked), unitless

pmin = Minimum ratio of reinforcing steel in a wall pier

with a Section Designer section that is designed(not checked), unitless

tp = Thickness of a wall pier, inches This can be

dif-ferent at the top and bottom of the pier

ts = Thickness of a wall spandrel, inches This can be

different on the left and right end of the spandrel

ΣDL = The sum of all dead load cases

ΣLL = The sum of all live load cases

ΣRLL = The sum of all reduced live load cases

α = The angle between the diagonal reinforcing and

the longitudinal axis of a coupling beam

β1 = Unitless factor defined in Section 1910.2.7.3 of

the 1997 UBC

ε = Reinforcing steel strain, unitless

εs = Reinforcing steel strain in a wall pier, unitless

N ε 's = Compression steel strain in a wall spandrel,

unitless

φ = Strength reduction factor, unitless

φb = Strength reduction factor for bending, unitless

The default value is 0.9

φc = Strength reduction factor for bending plus high

axial compression in a concrete pier, unitless Thedefault value is 0.7

φvns = Strength reduction factor for shear in a

nonseis-mic pier or spandrel, unitless The default value is0.85

φvs = Strength reduction factor for shear in a seismic

pier or spandrel, unitless The default value is 0.6

ρ = Reliability/redundancy factor specified in Section

1630.1.1 of the 1997 UBC, unitless

σs = Reinforcing steel stress in a wall pier, psi

Chapter 1

Introduction

ETABS features powerful and completely integrated modules forthe design of steel and concrete frames, composite beams andconcrete shear walls This manual documents design of concreteshear walls using the 1997 UBC in ETABS The goal of thismanual is to provide you with all of the information required toreproduce the ETABS Shear Wall Design postprocessor resultsusing hand calculations

Overview

ETABS shear wall design is fully integrated into the ETABSgraphical user interface The ETABS graphical interface pro-vides an environment where you can easily design shear walls,study the design results, make appropriate changes (such as re-vising member properties) and re-examine the design results

Designs are based on a set of ETABS-defined default designload combinations that can be supplemented by user-definedload combinations

You have complete control over the program output You canview or print as much or as little design output as necessary.The ETABS Shear Wall Design postprocessor designs both wallpiers and wall spandrels The following two subsections discusseach of these items

Wall Pier Design

The ETABS Shear Wall Design postprocessor can perform

two-or three-dimensional designs of wall piers When ETABS signs a wall pier it considers flexural reinforcement, shear rein-forcement and boundary element requirements There are threedifferent options available in ETABS for the consideration offlexural reinforcement They are:

de-1 Perform a simplified design that yields concentrated areas ofreinforcing at the ends of the pier The pier design geometryused in this simplified design is defined in the pier designoverwrites This option is only available if you perform atwo-dimensional design of the pier

2 Use Section Designer to specify the pier design geometryand rebar layout For this option, the important items in the

rebar layout are the bar location and the relative size of each

bar (relative to other bars) ETABS then reports the age of reinforcing steel required to resist the applied loadsbased on your pier geometry and rebar layout It also reportsthe percentage of reinforcing steel actually specified in yourrebar layout so that you can gain some perspective on theactual bar sizes that might be required This option is avail-able for both two- and three-dimensional design of the pier

percent-3 Use Section Designer to specify the pier design geometryand rebar layout For this option, the important items in the

rebar layout are the bar location and the actual size of each

bar ETABS then reports the maximum demand capacity tio for the pier based on the pier geometry and rebar layout

ra-We strongly recommend that even if you initially use one ofthe other design options that you always complete your pierdesign using this option This pier design option allows you

to verify your final design and it is available for both and three-dimensional design of the pier

When the flexural design for the pier is based on a simplifiedsection (item 1 above), the shear design and boundary check areperformed at the top and bottom of the pier and are based on thesame simplified section

When the flexural design is based on a Section Designer section(items 2 and 3 above) , the shear design and boundary check areperformed at the bottom of the pier only and are based on an ef-fective rectangular section The process ETABS uses to derivethe dimensions for this effective rectangular section is described

in Chapter 6 You can revise the dimensions of this effectivesection in the pier design overwrites For three-dimensional pierstwo effective sections are defined One is for shear in the pier lo-cal 2-axis direction and the other is for shear in the pier local 3-axis direction

Note that when the ETABS Shear Wall Design postprocessorchecks specified flexural reinforcing (item 3 above), it designsthe shear reinforcing There is no mechanism available inETABS to specify the pier shear reinforcing and have it verified

by the program

Wall Spandrel Design

In ETABS wall spandrels must be two-dimensional WhenETABS designs a wall spandrel it reports required areas of con-centrated flexural reinforcement at the top and bottom of thespandrel, and the required shear reinforcement

The spandrel design geometry is defined in the spandrel designoverwrites The design geometry may be either a rectangularbeam or a T-beam

ETABS only designs spandrels; it does not check them There is

no mechanism available in ETABS to specify the spandrel forcing (flexural or shear reinforcing) and have it verified by theprogram

rein-1 Organization of Manual

This manual is organized as follows:

• Chapter 1 (this chapter): General introduction.

• Chapters 2 through 4: Information on how to use

ETABS to design shear walls

• Chapters 5 through 10: Documentation of background

information for 1997 UBC concrete shear wall designusing ETABS

• Chapters 11 through 15: Documentation of the 1997

UBC concrete shear wall design algorithm used byETABS

• Chapters 16 through 19: Documentation of the 1997

UBC concrete shear wall output

Other Reference Information

ETABS Help

You can access the ETABS Help by clicking the Help menu >

Search for Help On command You can also access

context-sensitive help by pressing the F1 function key on your keyboardwhen a dialog box is displayed

Readme.txt File

Be sure to read the readme.txt file that is on your CD This vides the latest information about the program Some of the in-formation in the readme.txt file may provide updates to what ispublished in this manual If you download an updated version ofthe program be sure to download and read the updatedreadme.txt file

this manual and

then use the

rest of the

man-ual as a

refer-ence guide on

an as-needed

basis.

Recommended Initial Reading

We recommend that you initially read Chapters 1 through 10 ofthis manual You can then use the remainder of this manual as areference on an as-needed basis

Chapter 2

Shear Wall Design Process

This chapter describes three typical shear wall design processesthat might occur for a new building Note that the sequence ofsteps you may take in any particular design may vary from thisbut the basic process will be essentially the same

The design process used varies slightly depending on the type ofwall pier design that you want to do The three types of pier de-sign considered in this chapter are:

• Two-dimensional pier design resulting in concentratedreinforcing at the ends of the piers

• Two-dimensional pier design resulting in relatively formly distributed reinforcing in the piers

uni-• Three dimensional pier design

Typical Design Process for 2D Piers with

Concentrated Reinforcing

1 Use the Options menu > Preferences > Shear Wall Design

command to review the shear wall design preferences andrevise them if necessary Note that there are default valuesprovided for all shear wall design preferences so it is notactually necessary for you to define any preferences unlessyou want to change some of the default preference values

2 Create the building model

3 Assign the wall pier and wall spandrel labels Use the Assign

menu > Frame/Line > Pier Label, the Assign menu > Shell/Area > Pier Label, the Assign menu > Frame/Line > Spandrel Label, and the Assign menu > Shell/Area > Spandrel Label commands to do this Refer to the ETABS

User's Manual for additional information on pier and drel labeling

span-4 Run the building analysis using the Analyze menu > Run

Analysis command.

5 Assign shear wall overwrites, if needed, using the Design

menu > Shear Wall Design > View/Revise Pier writes and the Design menu > Shear Wall Design > View/Revise Spandrel Overwrites commands Note that

Over-you must select piers or spandrels first before using thesecommands Also note that there are default values providedfor all pier and spandrel design overwrites so it is not actu-ally necessary for you to define any overwrites unless youwant to change some of the default overwrite values

Note that the overwrites can be assigned before or after theanalysis is run

Important note about selecting piers and spandrels: You

can select a pier or spandrel simply by selecting any line orarea object that is part of the pier or spandrel

6 If you want to use any design load combinations other thanthe default ones created by ETABS for your shear wall de-

sign then click the Design menu > Shear Wall Design >

Select Design Combo command Note that you must have

already created your own design combos by clicking the

De-fine menu > Load Combinations command.

7 Click the Design menu > Shear Wall Design > Start

De-sign/Check of Structure command to run the shear wall

de-sign

8 Review the shear wall design results To do this you might

do one of the following:

a Click the Design menu > Shear Wall Design > Display

Design Info command to display design input and

out-put information on the model

b Right click on a pier or spandrel while the design resultsare displayed on it to enter the interactive wall designmode Note that while you are in this mode you can re-vise overwrites and immediately see the new design re-sults

If you are not currently displaying design results you can

click the Design menu > Shear Wall Design >

Interac-tive Wall Design command and then right click a pier or

spandrel to enter the interactive design mode for thatelement

c Use the File menu > Print Tables > Shear Wall

De-sign command to print shear wall deDe-sign data If you

select a few piers or spandrels before using this mand then data is printed only for the selected elements

com-9 If desired, revise the wall pier and/or spandrel overwrites, run the shear wall design, and review the results again Re-peat this step as many times as needed

re-10 Create wall pier check sections with user-defined (actual)reinforcing specified for the wall piers using the Section De-

signer utility Use the Design menu > Shear Wall Design >

Define Pier Sections for Checking command to define the

sections in Section Designer Be sure to indicate that the

inforcing is to be checked in the Pier Section Data dialog

box Use the Design menu > Shear Wall Design > Assign

Pier Sections for Checking command to assign these

sec-tions to the piers Rerun the design and verify that the actualflexural reinforcing provided is adequate

11 If necessary, revise the geometry or reinforcing in the tion Designer section and rerun the design check

Sec-12 Print or display selected shear wall design results if desired.Note that shear wall design is performed as an iterative process.You can change your wall design dimensions and reinforcingduring the design process without rerunning the analysis

Typical Design Process for 2D Piers with Uniform Reinforcing

13 Use the Options menu > Preferences > Shear Wall Design

command to review the shear wall design preferences andrevise them if necessary Note that there are default valuesprovided for all shear wall design preferences so it is notactually necessary for you to define any preferences unlessyou want to change some of the default preference values

14 Create the building model

15 Assign the wall pier and wall spandrel labels Use the Assign

menu > Frame/Line > Pier Label, the Assign menu > Shell/Area > Pier Label, the Assign menu > Frame/Line > Spandrel Label, and the Assign menu > Shell/Area > Spandrel Label commands to do this Refer to the ETABS

User's Manual for additional information on pier and drel labeling

span-16 Run the building analysis using the Analyze menu > Run

17 Assign shear wall overwrites, if needed, using the Design

menu > Shear Wall Design > View/Revise Pier writes and the Design menu > Shear Wall Design > View/Revise Spandrel Overwrites commands Note that

Over-you must select piers or spandrels first before using thesecommands Also note that there are default values providedfor all pier and spandrel design overwrites so it is not actu-ally necessary for you to define any overwrites unless youwant to change some of the default overwrite values

Note that the overwrites can be assigned before or after theanalysis is run

Important note about selecting piers and spandrels: You

can select a pier or spandrel simply by selecting any line orarea object that is part of the pier or spandrel

18 If you want to use any design load combinations other thanthe default ones created by ETABS for your shear wall de-

sign then click the Design menu > Shear Wall Design >

Select Design Combo command Note that you must have

already created your own design combos by clicking the

De-fine menu > Load Combinations command.

19 Create wall pier design sections with actual rebar placementspecified for the wall piers using the Section Designer util-

ity Use the Design menu > Shear Wall Design > Define

Pier Sections for Checking command to define the sections

in Section Designer Be sure to indicate that the reinforcing

is to be designed in the Pier Section Data dialog box Use the

Design menu > Shear Wall Design > Assign Pier Sections for Checking command to assign these sections to the piers.

Note that at this point the actual bar size specified in theSection Designer pier sections is not important What is im-portant is the relative bar size, that is, the size of one rebar inthe pier section to the other bars in the section The programalways maintains this relationship

20 Click the Design menu > Shear Wall Design > Start

De-sign/Check of Structure command to run the shear wall

21 Review the shear wall design results To do this you might

do one of the following:

a Click the Design menu > Shear Wall Design > Display

Design Info command to display design input and

out-put information on the model

b Right click on a pier or spandrel while the design resultsare displayed on it to enter the interactive wall designmode Note that while you are in this mode you can re-vise overwrites and immediately see the new design re-sults

If you are not currently displaying design results you can

click the Design menu > Shear Wall Design >

Interac-tive Wall Design command and then right click a pier or

spandrel to enter the interactive design mode for thatelement

c Use the File menu > Print Tables > Shear Wall

De-sign command to print shear wall deDe-sign data If you

select a few piers or spandrels before using this mand then data is printed only for the selected elements

com-22 If desired, revise the wall pier and/or spandrel overwrites, run the shear wall design, and review the results again Re-peat this step as many times as needed

re-23 Modify the Section Designer wall pier sections to reflect the

actual desired reinforcing bar location and sizes Use the

De-sign menu > Shear Wall DeDe-sign > Define Pier Sections for Checking command to modify the sections in Section De-

signer Be sure to indicate that the reinforcing is to be

checked (not designed) in the Pier Section Data dialog box.

Rerun the design and verify that the actual flexural ing provided is adequate

reinforc-24 If necessary, revise the geometry or reinforcing in the tion Designer section and rerun the design check

Sec-25 Print or display selected shear wall design results if desired

Note that shear wall design is performed as an iterative process.You can change your wall design dimensions and reinforcingduring the design process without rerunning the analysis

Typical Design Process for 3D Piers

1 Use the Options menu > Preferences > Shear Wall Design

command to review the shear wall design preferences andrevise them if necessary Note that there are default valuesprovided for all shear wall design preferences so it is notactually necessary for you to define any preferences unlessyou want to change some of the default preference values

2 Create the building model

3 Initially it is useful to perform a 2D design so that a shearcheck is performed Assign wall pier and wall spandrel la-

bels for the 2D design Use the Assign menu > Frame/Line

> Pier Label, the Assign menu > Shell/Area > Pier Label,

the Assign menu > Frame/Line > Spandrel Label, and the

Assign menu > Shell/Area > Spandrel Label commands to

do this Refer to the ETABS User's Manual for additional formation on pier and spandrel labeling

in-4 Run the building analysis using the Analyze menu > Run

Analysis command.

5 Assign shear wall overwrites, if needed, using the Design

menu > Shear Wall Design > View/Revise Pier writes and the Design menu > Shear Wall Design > View/Revise Spandrel Overwrites commands Note that

Over-you must select piers or spandrels first before using thesecommands Also note that there are default values providedfor all pier and spandrel design overwrites so it is not actu-ally necessary for you to define any overwrites unless youwant to change some of the default overwrite values

Note that the overwrites can be assigned before or after theanalysis is run

Important note about selecting piers and spandrels: You

can select a pier or spandrel simply by selecting any line orarea object that is part of the pier or spandrel

6 If you want to use any design load combinations other thanthe default ones created by ETABS for your shear wall de-

sign then click the Design menu > Shear Wall Design >

Select Design Combo command Note that you must have

already created your own design combos by clicking the

De-fine menu > Load Combinations command.

7 Click the Design menu > Shear Wall Design > Start

De-sign/Check of Structure command to run the shear wall

de-sign

8 Review the shear wall design results To do this you might

do one of the following:

a Click the Design menu > Shear Wall Design > Display

Design Info command to display design input and

out-put information on the model

b Right click on a pier or spandrel while the design resultsare displayed on it to enter the interactive wall designmode Note that while you are in this mode you can re-vise overwrites and immediately see the new design re-sults

If you are not currently displaying design results you can

click the Design menu > Shear Wall Design >

Interac-tive Wall Design command and then right click a pier or

spandrel to enter the interactive design mode for thatelement

c Use the File menu > Print Tables > Shear Wall

De-sign command to print shear wall deDe-sign data If you

select a few piers or spandrels before using this mand then data is printed only for the selected elements

com-9 If desired, revise the wall pier and/or spandrel overwrites, run the shear wall design, and review the results again Re-peat this step as many times as needed

10 When you are satisfied with the shear design, relabel the

wall piers so that you can perform a 3D design Use the

As-sign menu > Frame/Line > Pier Label and the AsAs-sign menu > Shell/Area > Pier Label commands to do this Re-

fer to the ETABS User's Manual for additional information

on pier and spandrel labeling

11 Create wall pier design sections with actual rebar placementspecified for the wall piers using the Section Designer util-

ity Use the Design menu > Shear Wall Design > Define

Pier Sections for Checking command to define the sections

in Section Designer Be sure to indicate that the reinforcing

is to be designed in the Pier Section Data dialog box Use the

Design menu > Shear Wall Design > Assign Pier Sections for Checking command to assign these sections to the piers.

Note that at this point the actual bar size specified in theSection Designer pier sections is not important What is im-portant is the relative bar size, that is, the size of one rebar inthe pier section to the other bars in the section The programalways maintains this relationship

12 Click the Design menu > Shear Wall Design > Start

De-sign/Check of Structure command to run the shear wall

de-sign

13 Review the shear wall design results

14 If desired, revise the wall pier and/or spandrel overwrites, run the shear wall design, and review the results again Re-peat this step as many times as needed

re-15 Modify the Section Designer wall pier sections to reflect the

actual desired reinforcing bar location and sizes Use the

De-sign menu > Shear Wall DeDe-sign > Define Pier Sections for Checking command to modify the sections in Section De-

signer Be sure to indicate that the reinforcing is to be

checked (not designed) in the Pier Section Data dialog box.

Rerun the design and verify that the actual flexural ing provided is adequate

reinforc-16 If necessary, revise the geometry or reinforcing in the tion Designer section and rerun the design check

17 Print or display selected shear wall design results if desired.Note that shear wall design is performed as an iterative process.You can change your wall design dimensions and reinforcingduring the design process without rerunning the analysis

com-mands by clicking Design menu > Shear Wall Design.

Select Design Combo

Click the Design menu > Shear Wall Design > Select Design

Combo command to open the Design Load Combinations

Se-lection dialog box Here you can review the default shear walldesign load combinations defined by ETABS and/or you candesignate your own design load combinations

In the dialog box all of the available design load combinationsare listed in the List of Combos list box The design load combi-nations actually used in the design are listed in the Design Com-

bos list box You can use the Add button and the Remove button

to move load combinations into and out of the Design Combos

list box Use the Show button to see the definition of a design

load combination All three buttons act on the highlighted designload combination You can use the Ctrl and Shift keys to make

multiple selections in this dialog box for use with the Add and

Remove buttons, if desired.

The default shear wall design load combinations have names likeDWAL1, etc

View/Revise Pier Overwrites

Use the Design menu > Shear Wall Design > View/Revise Pier

Overwrites command to review and/or change the wall pier

overwrites You may not need to assign any wall pier overwrites;however the option is always available to you

The wall pier design overwrites are basic properties that applyonly to the piers that they are specifically assigned to Note thatinputting 0 for most pier overwrite items means to use theETABS default value for that item

You can select one or more piers for which you want to specifyoverwrites In the overwrites form there is a checkbox to the left

of each item You must check this box for any item you want tochange in the overwrites If the check box for an overwrite item

is not checked when you click the OK button to exit the

over-writes form, then no changes are made to the pier overwrite item.This is true whether you have one pier selected or multiple piersselected

View/Revise Spandrel Overwrites

Use the Design menu > Shear Wall Design > View/Revise

Spandrel Overwrites command to review and/or change the

wall spandrel overwrites You may not need to assign any wallspandrel overwrites; however the option is always available toyou

The wall spandrel design overwrites are basic properties that ply only to the spandrels that they are specifically assigned to.Note that inputting 0 for most spandrel overwrite items means touse the ETABS default value for that item