Composite Design Manual (ETAB Ver. 8)

8/8/2019 Composite Design Manual (ETAB Ver. 8)

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Computers and Structures, Inc.Berkeley, California, USA

Version 8January 2002

ETABS

Integrated Building Design Software

Composite Floor Frame Design Manual


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Copyright Computers and Structures, Inc., 1978-2002.The CSI Logo is a trademark of Computers and Structures, Inc.

ETABS is a trademark of Computers and Structures, Inc.Windows is a registered trademark of Microsoft Corporation.

Adobe and Acrobat are registered trademarks of Adobe Systems Incorporated

Copyright

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) 845-4096

e-mail: [email protected] (for general questions)e-mail: [email protected] (for technical support questions)

web: www.csiberkeley.com


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DISCLAIMER

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 WARRANTYIS EXPRESSED OR IMPLIED BY THE DEVELOPERS OR THE DISTRIBUTORSON THE ACCURACY OR THE RELIABILITY OF THE PROGRAM.

THIS PROGRAM IS A VERY PRACTICAL TOOL FOR THE DESIGN/CHECK OFSTEEL STRUCTURES. HOWEVER, THE USER MUST THOROUGHLY READ THE

MANUAL AND CLEARLY RECOGNIZE THE ASPECTS OF COMPOSITE DESIGNTHAT THE PROGRAM ALGORITHMS DO NOT ADDRESS.

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


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COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA DECEMBER 2001

COMPOSITE BEAM DESIGN

Contents

General Composite Beam Design Information

1 General Design Information

Design Codes 1-1

Units 1-1

Beams Designed as Composite Beams 1-1

Material Property Requirements for Com-

posite Beams 1-2

Other Requirements for Composite

Beams 1-2

Frame Elements Designed by Default as

Composite Beams 1-3

Overwriting the Frame Design Procedure

for a Composite Beam 1-3

How the Program Optimizes Design Groups 1-5

Using Price to Select Optimum Beam

Sections 1-6

Design Load Combinations 1-8

Analysis Sections and Design Sections 1-8

Output Stations 1-10

2 Composite Beam Design Process

Design Process for a New Building 2-1

Check Process for an Existing Building 2-4

3 Interactive Composite Beam Design

Member Identification 3-1

Section Information 3-2

Acceptable Sections List 3-3

ReDefine 3-4


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Composite Beam Design Manual

ii

Temporary 3-5

Show Details 3-5

4 Output Data Plotted Directly on the Model

Overview 4-1

Labels Displayed on the Model 4-2

Design Data 4-3

Stress Ratios 4-4

Deflection Ratios 4-5

5 Input Data

General 5-1

Using the Print Composite Beam Design

Tables Form 5-1

Material Properties Input Data 5-2

Section Properties Input Data 5-3

Deck Properties Input Data 5-4

Design Preferences Input Data 5-6

Beam Overwrites Input Data 5-8

6 Output Data

Overview 6-1

Using the Print Composite Beam Design

Tables Form 6-1Summary of Composite Beam Output 6-2

7 Composite Beam Properties

Beam Properties 7-1

Metal Deck and Slab Properties 7-3

Shear Stud Properties 7-5

Cover Plates 7-5

8 Effective Width of Concrete SlabLocation Where Effective Slab Width is

Checked 8-1

Multiple Deck Types or Directions Along the

Beam Length 8-2

Effect of Diagonal Beams on Effective Slab

Width 8-6


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Contents

iii

Effect of Openings on Effective Slab

Width 8-8

Effective Slab Width and Transformed

Section Properties 8-9

9 Beam Unbraced Length

Overview 9-1

Determination of the Braced Points of a

Beam 9-2

User-Defined Unbraced Length of a Beam

Overview 9-3

User-Specified Uniform and Point

Bracing 9-4

Design Check Locations 9-7

10 Design Load Combinations

Overview 10-1

Special Live Load Patterning for

Cantilever Back Spans 10-2

Special Live Load Patterning for

Continuous Spans 10-4

11 Beam Deflection and Camber

Deflection 11-1Camber 11-4

12 Beam Vibration

Overview 12-1

Vibration Frequency 12-1

Murray's Minimum Damping Requirement 12-4

Initial Displacement Amplitude 12-4

Effective Number of Beams Resisting

Heel Drop Impact 12-6References 12-7

13 Distribution of Shear Studs on a Composite

Beam

Overview 13-1

Composite Beam Segments 13-1


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iv

Physical End of the Beam Top Flange 13-2

Distribution of Shear Studs Within a

Composite Beam Segment 13-5

How the Program Distributes Shear Studs

on a Beam 13-5

Equations Used When the Program

Works from Left to Right 13-8

Equations Used When the Program

Works from Right to Left 13-9

Minimum and Maximum Number of

Shear Studs in a Composite Beam

Segment 13-11

A Note About Multiple Design Load

Combinations 13-11

14 The Number of Shear Studs that Fit in a

Composite Beam Segment

General 14-1

Solid Slab or Deck Ribs Oriented Parallel to

Beam Span 14-2

Deck Ribs Oriented Perpendicular to Beam

Span 14-6

Different Deck Type or Orientation on Beam

Sides 14-8

15 User-Defined Shear Stud Patterns

Specifying a User-Defined Shear Connector

Pattern 15-1

Uniformly Spaced Shear Studs Over the

Length of the Beam 15-2

Additional Shear Studs in Specified Sections

of Beam 15-4

Defining Additional Beam Sections 15-4

Example of a User-Defined Shear Stud

Pattern 15-8

How the Program Checks a Beam with User-

Defined Shear Studs 15-9


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Contents

v

Composite Beam Design Specific to AISC-ASD89

16 General and Notation

Introduction to the AISC-ASD89 Series of

Technical Notes 16-1

Notation 16-2

17 Preferences

General 17-1

Using the Preferences Form 17-1

Preferences 17-2

Factors Tab 17-3

Beam Tab 17-3

Deflection Tab 17-4

Vibration Tab 17-5

Price Tab 17-6

18 Overwrites

General 18-1

Using the Composite Beam Overwrites

Form 18-2

Overwrites 18-3

Beam Tab 18-4Bracing (C) Tab and Bracing Tab 18-6

Deck Tab 18-9

Shear Studs Tab 18-10

Deflection Tab 18-13

Vibration Tab 18-14

Miscellaneous Tab 18-14

EQ Factor 18-15

19 Width-to-Thickness ChecksOverview 19-1

Limiting Width-to-Thickness Ratios for

Flanges 19-2

Compact Section Limits for Flanges 19-2

Noncompact Section Limits for

Flanges 19-2


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Contents

vii

Allowable Bending Stress for Steel Beam

Alone 22-2

Allowable Bending Stresses for Positive

Bending in the Composite Beam 22-6

23 Bending Stress Checks

Bending Stress Checks Without

Composite Action 23-1

Positive Moment in a Composite Beam 23-2

Important Notes Regarding Unshored

Composite Beams 23-5

Steel Stress Checks 23-5

Concrete Stress Checks 23-6

24 Beam Shear Checks

Shear Stress Check 24-1

Typical Case 24-1

Slender Web 24-2

Copes 24-3

Shear Rupture Check 24-4

Limitations of Shear Check 24-7

25 Shear Studs

Overview 25-1Shear Stud Connectors 25-1

Reduction Factor when Metal Deck is

Perpendicular to Beam 25-2

Reduction Factor when Metal Deck is

Parallel to Beam 25-3

Horizontal Shear for Full Composite

Connection 25-4

Number of Shear Studs 25-5

Between the Output Station withMaximum Moment and the

Point of Zero Moment 25-6

Between Other Output Stations and

Points of Zero Moment 25-6


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Contents

ix

Deck Tab 31-9

Shear Studs Tab 31-10

Deflection Tab 31-12

Vibration Tab 31-13

Miscellaneous Tab 31-14

32 Design Load Combinations

Strength Check for Construction Loads 32-1

Strength Check for Final Loads 32-2

Deflection Check for Final Loads 32-2

Reference 32-3

33 Compact and Noncompact Requirements

Overview 33-1


Flanges 33-2

Compact Section Limits for Flanges 33-2

Noncompact Section Limits for

Flanges 33-2


Webs 33-3

Compact Section Limits for Webs 33-3

Noncompact Section Limits for Webs 33-4


Cover Plates 33-5

Compact Section Limits for Cover

Plates 33-5

Noncompact Section Limits for Cover

Plates 33-6

34 Composite Plastic Moment Capacity for

Positive Bending

Overview 34-1Location of the Plastic Neutral Axis 34-2

PNA in the Concrete Slab Above

the Steel Beam 34-5

PNA within the Beam Top Flange 34-8

PNA within the Beam Top Fillet 34-9

PNA within the Beam Web 34-10


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x

PNA within the Beam Bottom Fillet 34-11

PNA within the Beam Bottom Flange 34-12

PNA within the Cover Plate 34-13

Calculating the PNA Location 34-15

Plastic Moment Capacity for Positive

Bending 34-16

35 Composite Section Elastic Moment

Capacity

Positive Moment Capacity with an Elastic Stress

Distribution 35-1

36 Moment Capacity for Steel Section Alone

Overview 36-1

Steel Beam Properties 36-1

Moment Capacity for a Doubly Symmetric Beam

or a Channel Section 36-2

Lateral Unbraced Length Checks 36-3

Yielding Criteria in AISC-LRFD93 Section

F1.1 36-5

Lateral Torsional Buckling Criteria in

AISC-LRFD93 Section F1.2a 36-5

AISC-LFRD Appendix F1(b) Equation

A-F1-3 46-5

Moment Capacity for a Singly Symmetric

Beam with a Compact Web 36-7

AISC-LFRD93 Equation A-F1-1 for

WLB 36-8

AISC-FLRD93 Equation A-F1-1 for

FLB 36-8


FLB 36-9


LTB 36-9


LTB 36-10

Moment Capacity for a Singly Symmetric

Beam with a Noncompact Web 36-11


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Contents

xi

AISC-LFRD93 Equation A-F1-3 for

WLB 36-12

37 Partial Composite Connection with a Plas-

tic Stress Distribution

Estimating the Required Percent Composite

Connection 37-1

Calculating MPFconc 37-2

Location of PNA 37-3

Determining the Effective Portion of

the Concrete Slab 37-4

Moment Capacity of a Partially Composite

Beam with a Plastic Stress

Distribution 37-6

38 Bending and Deflection Checks

Bending Check Locations 38-1

Bending Check 38-1

Deflection Check 38-2

39 Shear Connectors

Shear Stud Connectors 39-1

Horizontal Shear for Full Composite

Connection 39-1Number of Shear Connectors 39-2

Between Maximum Moment and

Point of Zero Moment 39-2

Between Point Load and Point of

Zero Moment 39-3

40 Beam Shear Capacity

Shear Capacity 40-1

Checking the Beam Shear 40-2Limitations of Beam Shear Check 40-2

41 Input Data

Beam Overwrites Input 41-1


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20/420Design Codes Technical Note 1 - 1



Technical Note 1

General Design Information

This Technical Note presents some basic information and concepts that are

useful when performing composite beam design using this program.

Design Codes

The design code is set using the Options menu > Preferences > Compos-

ite Beam Design command. You can choose to design for any one design

code in any one design run. You cannot design some beams for one code and

others for a different code in the same design run. You can however perform

different design runs using different design codes without rerunning the

analysis.

Units

For composite beam design in this program, any set of consistent units can be

used for input. Typically, design codes are based on one specific set of units.

The documentation in the Composite Beam Design series of Technical Notes is

presented in kip-inch-seconds units unless otherwise noted.

Again, any system of units can be used to define and design a building in the

program. You can change the system of units at any time using the pull-down

menu on the Status Bar or pull-down menu on individual forms where avail-

able.

Note:

You can use any set of units in composite beam design and you can change the units "onthe fly."

Beams Designed as Composite BeamsSection Requirements for Composite Beams

Only I-shaped and channel-shaped beams can be designed as composite

beams. The I-shaped and channel-shaped beams can be selected from the


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General Design Information Composite Beam Design

Technical Note 1 - 2 Beams Designed as Composite Beams

built-in program section database, or they can be user defined. The user-

defined sections can be specified using the Define menu > Frame Sections

command and clicking either the Add I/Wide Flange or the Add Channel op-

tion.

Note that beam sections that are defined in Section Designer are always

treated as general sections. Thus, if you define an I-type or channel-type

section in Section Designer, the program will consider it as a general section,

not an I-shaped or channel-shaped section, and will not allow it to be de-

signed as a composite beam.

Note:

Beam sections defined in the section designer utility cannot be designed as compositebeams.

Material Property Requirement for Composite Beams

If a beam is to be designed as a composite beam, the Type of Design associ-

ated with the Material Property Data assigned to the beam mustbe Steel. Use

the Define menu > Material Properties > Modify/Show Materials com-

mand to check your beams.

Other Requirements for Composite Beams

The line type associated with the line object that represents a composite

beam must be "Beam." In other words, the beam element must lie in a hori-

zontal plane. Right click on a line object to bring up the Line Information form

to check the Line Type.

For composite beams, the beam local 2-axis must be vertical. The Local axis 2

Angle is displayed on the Assignments tab of the Line Information form.

Note:

The line object representing a composite beam should span from support to support.Composite beams should not be modeled using multiple, adjacent line objects betweensupports for a single composite beam.

The line object representing a composite beam should span from support to

support. In the case of a cantilever beam overhang, the line object should

span from the overhang support to the end of the beam. The cantilever beam

back span should be modeled using a separate line object. If you do not

model cantilever beams in this way, the analysis results for moments and


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Composite Beam Design General Design Information

Beams Designed as Composite Beams Technical Note 1 - 3

shears will still be correct but the design performed by the Composite Beam

Design processor probably will not be correct.

Frame Elements Designed by Default as Composite Beams

The program will design certain frame elements using the design procedures

documented in these Technical Notes by default. Those elements must meet

the following restrictions:

The beam must meet the section requirements described in the subsection

entitled "Section Requirements for Composite Beams" in this Technical

Note.

The beam must meet the material property requirement described in the

subsection entitled "Material Property Requirement for Composite Beams"

in this Technical Note.

The beam must meet the two other requirements described in the subsec-

tion entitled "Other Requirements for Composite Beams" in this Technical

Note.

At least one side of the beam must support deck that is specified as a

Deck section (not a Slab or Wall section). The deck section can be filled,

unfilled or a solid slab. When the deck is unfilled, the beam will still go

through the Composite Beam Design postprocessor and will simply be de-

signed as a noncomposite beam.

The beam must not frame continuously into a column or a brace. Both

ends of the beam must be pinned for major axis bending (bending about

the local 3-axis).

Overwriting the Frame Design Procedure for a Composite Beam

The three procedures possible for steel beam design are:

Composite beam design

Steel frame design

No design

By default, steel sections are designed using either the composite beam de-

sign procedure or the steel frame design procedure. All steel sections that


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Technical Note 1 - 4 Beams Designed as Composite Beams

meet the requirements described in the previous subsection entitled "Frame

Elements Designed by Default as Composite Beams" are by default designed

using the composite beam design procedures. All other steel frame elements

are by default designed using the steel frame design procedures.

Change the default design procedure used for a beam(s) by selecting the

beam(s) and clicking Design menu > Overwrite Frame Design Proce-

dure. This change is only successful if the design procedure assigned to an

element is valid for that element. For example, if you select two steel beams,

one an I-section and the other a tube section, and attempt to change the de-

sign procedure to Composite Beam Design, the change will be executed for

the I-section, but not for the tube section because it is not a valid section for

the composite beam design procedure. A section is valid for the composite

beam design procedure if it meets the requirements specified in the subsec-

tions entitled "Section Requirements for Composite Beams," "Material Prop-

erty Requirement for Composite Beams" and "Other Requirements for Com-

posite Beams" earlier in this Technical Note.

Note that the procedures documented for composite beam design allow for

designing a beam noncompositely. One of the overwrites available for com-

posite beam design is to specify that selected beams are either designed as

composite, noncomposite but still with a minimum number of shear studs

specified, or noncomposite with no shear studs. These overwrites do not af-

fect the design procedure. Changing the overwrite to one of the noncompositedesigns does not change the design procedure from Composite Beam Design

to Steel Frame Design. The noncomposite design in this case is still performed

from within the Composite Beam Design postprocessor.

Using the composite beam design procedure, out-of-plane bending is not con-

sidered and slender sections are not designed. This is different from the Steel

Frame Design postprocessor. Thus, the design results obtained for certain

beams may be different, depending on the design procedure used.

Finally, note that you can specify that the composite beam design procedures

are to be used for a beam even if that beam does not support any deck, or for

that matter, even if no slab is specified. In these cases, the beam will be de-

signed as a noncomposite beam by the Composite Beam Design postproces-

sor.


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How the Program Optimizes Design Groups Technical Note 1 - 5

How the Program Optimizes Design Groups

This section describes the process the program uses to select the optimum

section for a design group. In this description, note the distinction between

the term section, which refers to a beam section in an auto select section

list, and the term beam, which refers to a specific element in the design

group.

When considering design groups, the program first discards any beam in the

design group that is not assigned an auto select section list.

Next, the program looks at the auto select section list assigned to each beam

in the design group and creates a new list that contains the sections that are

common to all of the auto select section lists in the design group. The pro-

gram sorts this new common section list in ascending order, from smallestsection to largest section based on section weight (area).

Note:

When designing with design groups, the program attempts to quickly eliminate inade-quate beams.

The program then finds the beam with the largest positive design moment in

the design group, or the "pseudo-critical beam." The program then checks the

design of the pseudo-critical beam for all sections in the common section list.

Any sections in the common section list that are not adequate for the pseudo-

critical beam are discarded from the common section list, making the list

shorter. This new list is the shorter common section list. The shorter common

section list is still in ascending order based on section weight (area).

Now the program checks all beams in the design group for the first section

(smallest by weight [area]) in the shorter common section list. If the optimi-

zation is being performed on the basis of beam weight and the section is ade-

quate for all beams in the design group, the optimum section has been iden-

tified. If the section is not adequate for a beam, the next higher section in theshorter common section list is tried until a section is found that is adequate

for all beams in the design group.

If the optimization is based on price instead of weight, the program finds the

first section in the shorter common section list (i.e., the one with the lowest

weight) that is adequate for all beams. Next it calculates the cost of this first


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Technical Note 1 - 6 Using Price to Select Optimum Beam Sections

adequate section and then determines the theoretical heaviest section that

could still have a cost equal to the adequate section by dividing the total price

of the beam with the adequate section (steel plus camber plus shear connec-

tors) by the unit price of the steel. This assumes that when the cost of the

steel section alone is equal to or greater than the total cost of the adequate

section, the section could not have a total cost less than the adequate sec-

tion. The program then checks any other sections in the shorter common sec-

tion list that have a weight less than or equal to the calculated maximum

weight. If any of the other sections are also adequate, a cost is calculated for

them. Finally, the section with the lowest associated cost is selected as the

optimum section for the design group.

Regardless of whether the optimization is based on weight or cost, if all sec-

tions in the shorter common section list are tried and none of them are ade-

quate for all of the beams in the design group, the program proceeds to de-

sign each beam in the design group individually based on its own auto section

list and ignores the rest of the design group. If for a particular beam none of

the sections in the auto select section list are adequate, the program displays

results for the section in the auto select list with the smallest controlling ratio

in a red font. Note that the controlling ratio may be based on stress or deflec-

tion.

Note:

By default, the program selects the optimum composite beam size based on weight, notprice.

Using Price to Select Optimum Beam Sections

By default, when auto select section lists are assigned to beams, the program

compares alternate acceptable composite beam designs based on the weight

of the steel beam (not including the cover plate, if it exists) to determine the

optimum section. The beam with the least weight is considered the optimum

section. The choice of optimum section does not consider the number of shear

connectors required or if beam camber is required.


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Analysis Sections and Design Sections Technical Note 1 - 9

The Design menu > Composite Beam Design > Verify Analysis vs De-

sign Section command is useful for this task.

The program keeps track of the analysis section and the design section

separately. Note the following about analysis and design sections:

Assigning a beam a frame section property using the Assign menu >

Frame/Line > Frame Section command assigns the section as both the

analysis section and the design section.

Running an analysis using the Analyze menu > Run Analysis command

(or its associated toolbar button) always sets the analysis section to be

the same as the current design section.

Assigning an auto select list to a frame section using the Assign menu >

Frame/Line > Frame Section command initially sets the design section

to be the beam with the median weight in the auto select list.

Unlocking a model deletes the design results, but it does not delete or

change the design section.

Using the Design menu > Composite Beam Design > Select Design

Combo command to change a design load combination deletes the design

results, but it does not delete or change the design section.

Using the Define menu > Load Combinations command to change a

design load combination deletes the design results, but it does not delete

or change the design section.

Using the Options menu > Preferences > Composite Beam Design

command to change any of the composite beam design preferences de-

letes the design results, but it does not delete or change the design sec-

tion.

Deleting the static nonlinear analysis results also deletes the design re-sults for any load combination that includes static nonlinear forces. Typi-

cally, static nonlinear analysis and design results are deleted when one of

the following actions is taken:

9 Use the Define menu > Frame Nonlinear Hinge Properties com-

mand to redefine existing or define new hinges.


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Technical Note 1 - 10 Output Stations

9 Use the Define menu > Static Nonlinear/Pushover Cases com-

mand to redefine existing or define new static nonlinear load cases.

9 Use the Assign menu > Frame/Line > Frame Nonlinear Hinges

command to add or delete hinges.

Again, note that these actions delete only results for load combinations that

include static nonlinear forces.

Output Stations

Frame output stations are designated locations along a frame element. They

are used as locations to report output forces and to perform design, and as

plotting points used for graphic display of force diagrams. When force dia-

grams are plotted, exact forces are plotted at each output station and then

those points are connected by straight lines. Output stations occur at user-

specified locations andat point load locations along a beam. Designate the

output stations for a frame element using the Assign menu.

Note:

Access the display of frame element output stations using the View menu.

For composite beam design, the program checks the moments, shears and

deflections at each output station along the beam. No checks are made at any

points along the beam that are not output stations.


30/420Design Process for a New Building Technical Note 2 - 1



Technical Note 2

Composite Beam Design Process

This Technical Notes describes a basic composite beam design process using

this program. Although the exact steps you follow may vary, the basic design

process should be similar to that described herein. Separate processes are

described for design of a new building and check of an existing building. Other

Technical Notes in the Composite Beam Design General series provide addi-

tional information.

Design Process for a New BuildingThe following sequence describes a typical composite beam design process for

a new building. Note that although the sequence of steps you follow may

vary, the basic process probably will be essentially the same.

1. Use the Options menu > Preferences > Composite Beam Design

command to choose the composite beam design code and to review other

composite beam design preferences and revise them if necessary. Note

that default values are provided for all composite beam design prefer-

ences, so it is unnecessary to define any preferences unless you want to

change some of the default values. See AISC-ASD89 Composite Beam De-

sign Technical Note 17 Preferences and AISC-LRFD93 Composite Beam

Design Technical Note 30 Preferences for more information about prefer-

ences.

2. Create the building model, as described in Volumes 1 and 2.

3. Run the building analysis using the Analyze menu > Run Analysis

command.

4. Assign composite beam overwrites, if needed, using the Design menu >

Composite Beam Design > View/Revise Overwrites command. Note

that you must select beams before using this command. Also note that

default values are provided for all composite beam design overwrites so it

is unnecessary to define overwrites unless you want to change some of


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Composite Beam Design Process Composite Beam Design

Technical Note 2 - 2 Design Process for a New Building

the default values. Note that the overwrites can be assigned before or af-

ter the analysis is run. See AISC-ASD89 Composite Beam Design Techni-

cal Note 18 Overwrites and See AISC-LRFD93 Composite Beam Design

Technical Note 31 Overwrites.

5. Designate design groups, if desired, using the Design menu > Compos-

ite Beam Design > Select Design Group command. Note that you

must have already created some groups by selecting objects and clicking

the Assign menu > Group Names command.

6. To use design load combinations other than the defaults created by the

program for composite beam design, click the Design menu > Compos-

ite Beam 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.

Note that for composite beam design, you specify separate design load

combinations for construction loading, final loading considering strength,

and final loading considering deflection. Design load combinations for each

of these three conditions are specified using the Design menu > Com-

posite Beam Design > Select Design Combo command. See Compos-

ite Beam Design Technical Note 10 Design Load Combinations.

7. Click the Design menu > Composite Beam Design > Start De-

sign/Check of Structure command to run the composite beam design.

8. Review the composite beam design results by doing one of the following:

a. Click the Design menu > Composite Beam Design > Display De-

sign Info command to display design input and output information on

the model. See Composite Beam Design Technical Note 4 Data Plotted

Directly on the Model.

b. Right click on a beam while the design results are displayed on it to

enter the interactive design mode and interactively design the beam.

Note that while you are in this mode, you can also view diagrams

(load, moment, shear and deflection) and view design details on the

screen. See Composite Beam Design Technical Note 3 Interactive

Composite Beam Design for more information.


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Technical Note 2 - 4 Check Process for an Existing Building

14.Repeat Steps 11, 12 and 13 as many times as necessary.

Note:

Composite beam design in the program is an iterative process. Typically, the analysisand design will be rerun multiple times to complete a design.

15.Select all beams and click the Design menu > Composite Beam Design

> Make Auto Select Section Null command. This removes any auto se-

lect section list assignments from the selected beams.

16.Rerun the building analysis using the Analyze menu > Run Analysis

command. Note that the beam section properties used for the analysis are

the last specified design section properties.

17.Click the Design menu > Composite Beam Design > Start De-

sign/Check of Structure command to rerun the composite beam design

with the new section properties. Review the results using the procedures

described above.

18.Click the Design menu > Composite Beam Design > Verify Analysis

vs Design Section command to verify that all of the final design sections

are the same as the last used analysis sections.

19.Use the File menu > Print Tables > Composite Beam Design com-

mand to print selected composite beam design results if desired. SeeAISC-ASD89 Composite Beam Design Technical Note 28 Output Details

and AISC-LRFD93 Composite Beam Design Technical Note 42 Output De-

tails

It is important to note that design is an iterative process. The sections used in

the original analysis are not typically the same as those obtained at the end

of the design process. Always run the building analysis using the final beam

section sizes and then run a design check using the forces obtained from that

analysis. Use the Design menu > Composite Beam Design > Verify

Analysis vs Design Section command to verify that the design sections are

the same as the analysis sections.

Check Process for an Existing Building

The following sequence is a typical composite beam check process for an ex-

isting building. In general, the check process is easier than the design process


34/420


35/420


Technical Note 2 - 6 Check Process for an Existing Building

b. Right click on a beam while the design results are displayed on it to

enter the interactive design and review mode and review the beam de-

sign. Note that while you are in this mode you can also view diagrams

(load, moment, shear and deflection) and view design details on the

screen. See Composite Beam Design Technical Note 3 Interactive

Composite Beam Design for more information.

If design results are not currently displayed (and the design has been

run), click the Design menu > Composite Beam Design > Inter-

active Composite Beam Design command and then right click a

beam to enter the interactive design mode for that beam.

c. Use the File menu > Print Tables > Composite Beam Design

command to print composite beam design data. If you select beams

before using this command, data is printed only for the selectedbeams.

d. Use the Design menu > Composite Beam Design > Verify all

Members Passed command to verify that no members are over-

stressed or otherwise unacceptable. See AISC-ASD89 Composite Beam

Design Technical Note 27 Input Data, AISC-LRFD93 Composite Beam

Design Technical Note 41 Input Data, AISC-ASD89 Composite Beam

Design Technical Note 28 Output Details, and AISC-LRFD93 Composite

Beam Design Technical Note 42 Output Details for more information.


36/420Member Identification Technical Note 3 - 1



Technical Note 3

Interactive Composite Beam Design

Interactive composite beam design is a powerful feature that allows the user

to review the design results for any composite beam and interactively revise

the design assumptions and immediately review the revised results.

Note that a design must have been run for the interactive design mode to be

available.

To enter the interactive design mode and interactively design the beam, right

click on a beam while the design results are displayedin the active window. If

design results are not displayed (and the design has been run), click the De-

sign menu > Composite Beam Design > Interactive Composite Beam

Design command and then right click a beam.

The following sections describe the features that are included in the Interac-

tive Composite Beam Design and Review form.

Member IdentificationStory ID

This is the story level ID associated with the composite beam.

Beam Label

This is the label associated with the composite beam.

Design Group

This list box displays the name of the design group that the beam is assigned

to if that design group was considered in the design of the beam. If the beam

is part of a design group but the design group was not considered in the de-sign, N/A is displayed. If the beam is not assigned to any design group,

"NONE" is displayed.

If a beam is redesigned as a result of a change made in the Interactive Com-

posite Beam Design and Review form, the design group is ignored and only

the single beam is considered. Thus, as soon as you design a beam in the


37/420

Interactive Composite Beam Design Composite Beam Design

Technical Note 3 - 2 Section Information

Interactive Composite Beam Design and Review form, the Design Group box

either displays N/A or None.

You cannot directly edit the contents of this list box.

Section InformationAuto Select List

This drop-down box displays the name of the auto select section list assigned

to the beam. If no auto select list has been assigned to the beam, NONE is

displayed. You can change this item to another auto select list or to NONE

while in the form and the design results will be updated immediately. If you

change this item to NONE, the design is performed for the Current De-

sign/Next Analysis section property.

Optimal

If an auto select section list is assigned to the beam, this list box displays the

optimal section as determined by beam weight or price, depending on what

has been specified in the composite beam preferences. If no auto select list is

assigned to the beam, N/A is displayed for this item.


Last Analysis

This list box displays the name of the section that was used for this beam inthe last analysis. Thus, the beam forces are based on a beam of this section

property. For the final design iteration, the Current Design/Next Analysis sec-

tion property and the Last Analysis section property should be the same.


Current Design/Next Analysis

This list box displays the name of the current design section property. If the

beam is assigned an auto select list, the section displayed in this form initially

defaults to the optimal section.

Tip:

The section property displayed for the Current Design/Next Analysis item is used by theprogram as the section property for the next analysis run.


38/420

Composite Beam Design Interactive Composite Beam Design

Acceptable Sections List Technical Note 3 - 3

If no auto select list has been assigned to the beam, the beam design is per-

formed for the section property specified in this edit box.

It is important to note that subsequent analyses use the section property

specified in this list box for the next analysis section for the beam. Thus, the

forces and moments obtained in the next analysis are based on this beam

size.

The Current Design/Next Analysis section property can be changed by clicking

the Sections button that is described later in this Technical Note.

Important note: Changes made to the Current Design/Next Analysis section

property are permanently saved (until you revise them again) if you click the

OK button to exit the Interactive Composite Beam Design and Review form. If

you exit the form by clicking the Cancel button, these changes are consid-ered temporary and are not permanently saved.

Acceptable Sections List

The Acceptable Sections List includes the following information for each beam

section that is acceptable for all considered design load combinations.

Section name

Steel yield stress, Fy

Connector layout

Camber

Ratio

Tip:

A single beam displayed in a red font in the Acceptable Sections List means that none ofthe sections considered were acceptable.

Typically, the ratio displayed is the largest ratio obtained considering the

stress ratios for positive moment, negative moment and shear for both con-

struction loads and final loads, as well as the stud ratio(s), deflection ratios,

and if they are specified to be considered when determining if a beam section

is acceptable, the vibration ratios.


39/420


Technical Note 3 - 4 ReDefine

If the beam is assigned an auto select list, many beam sections may be listed

in the Acceptable Sections List. If necessary, use the scroll bar to scroll

through the acceptable sections. The optimal section is initially highlighted in

the list.

If the beam is not assigned an auto select list, only one beam section will be

listed in the Acceptable Sections List. It is the same section as specified in the

Current Design/Next Analysis edit box.

At least one beam will always be shown in the Acceptable Sections List, even

if none of the beams considered are acceptable. When no beams are accept-

able, the program displays the section with the smallest maximum ratio in a

red font. Thus, a single beam displayed in a red font in the Acceptable Sec-

tions List means that none of the sections considered were acceptable.

ReDefineSections Button

Use the Sections button to change the Current Design/Next Analysis section

property. This button can designate a new section property whether the sec-

tion property is or is not displayed in the Acceptable Sections List.

When you click on the Sections button, the Select Sections form appears.

Assign any frame section property to the beam by clicking on the desired

property and clicking OK. Note that if an auto select list is assigned to the

beam, using the Sections button sets the auto select list assignment to

NONE.

Overwrites Button

Click the overwrites button to access and make revisions to the composite

beam overwrites and then immediately see the new design results. Modifying

some overwrites in this mode and exiting both the Composite Beam Over-

writes form and the Interactive Composite Beam Design and Review form by

clicking their respective OK buttons permanently saves changes made to theoverwrites.

Exiting the Composite Beam Overwrites form by clicking the OK button tem-

porarily saves changes. Subsequently exiting the Interactive Composite Beam

Design and Review form by clicking the Cancel button cancels the changes

made. Permanent saving of the overwrites does not occur until the OK but-


40/420


Temporary Technical Note 3 - 5

tons in both the Composite Beam Overwrites form and the Interactive Com-

posite Beam Design and Review form have been clicked.

Temporary

Combos ButtonClick this button to access and make temporaryrevisions to the design load

combinations considered for the beam. This is useful for reviewing the results

for one particular load combination, for example. You can temporarily change

the considered design load combinations to be just the one you are interested

in and review the results.

The changes made to the considered design load combinations using the

combos button are temporary. They are not saved when you exit the Interac-

tive Composite Beam Design and Review form, whether you click OK or Can-cel to exit it.

Show DetailsDiagrams Button

Clicking the Diagrams button displays a form with the following four types of

diagrams for the beam.

Applied loads

Shear

Moment

Deflection

The diagrams are plotted for specific design load combinations specified in the

form by the user.

Details ButtonClicking the Details button displays design details for the beam. The infor-mation displayed is similar to the short form output that can be printed using

the File menu > Print Tables > Composite Beam Design command. The

Technical Notes describe short form output.


41/420


Technical Note 3 - 6 Show Details

Note:

Stud Details Information is available using the Details button, but is not included in theshort form output printed using File Menu > Print Tables> Composite Beam Design.

Stud details information is one item included in the interactive design details

that is not included in the short form output details (and thus not described inAISC-ASD89 Composite Beam Design Technical Note 28 Output Details or

AISC-LRFD93 Composite Beam Design Technical Note 42 Output Details). This

information is provided in a table with six columns on the Stud Details tab.

The definitions of the column headings in this table are given in the following

bullet items.

Location: This is either Max Moment or Point Load. If it is Max Moment,

the information on the associated row applies to the maximum moment

location for the specified design load combination. If it is Point Load, theinformation on the associated row applies to the point load location for the

specified design load combination.

Distance: The distance of the Max Moment or Point Load location meas-

ured from the center of the support at the left end (I-end) of the beam.

Combo: The final strength design load combination considered for the as-

sociated row of the table.

L1 left: The dimension L1 left associated with the specified location. See"How the Program Distributes Shear Studs on a Beam" in Composite

Beam Design Technical Note 13 Distribution of Shear Studs on a Beamfor

more information.

Recall that L1 left is the distance from an output station to an adjacent point

of zero moment or physical end of the beam top flange, or physical end of

the concrete slab, measured toward the left end (I-end) of the beam.

L1 right: The dimension L1 right associated with the specified location. See

"How the Program Distributes Shear Studs on a Beam" in Composite

Beam Design Technical Note 13 Distribution of Shear Studs on a Beamfor

more information.

Recall that L1 right is the distance from an output station to an adjacent

point of zero moment or physical end of the beam top flange, or physical


42/420


Show Details Technical Note 3 - 7

end of the concrete slab, measured toward the right end (J-end) of the

beam

Studs: The number of shear studs required between the specified location

and adjacent points of zero moment, the end of the concrete slab, or the

end of the beam top flange.

The Stud Details table reports information at each maximum moment location

and each point load location (if any) for each final strength design load com-

bination.

The Stud Detail information allows you to report your shear studs in compos-

ite beam segments that are different from the default composite beam seg-

ments used by the program. See "Composite Beam Segments" in Composite

Beam Design Technical Note 13 Distribution of Shear Studs on a Beam for adefinition of composite beam segments. It is very important that you un-

derstand how the program defines composite beam segments, be-

cause in the composite beam output, the program reports the re-

quired number of shear studs in each composite beam segment. See

"How the Program Distributes Shear Studs on a Beam" in Composite Beam

Design Technical Note 13 Distribution of Shear Studs on a Beam for discus-

sion of how the program distributes shear studs along a beam.


43/420


44/420Overview Technical Note 4 - 1



Technical Note 4

Data Plotted Directly on the Model

This Technical Note describes the input and output data that can be plotted

directly on the model.

Overview

Use the Design menu > Composite Beam Design > Display Design Info

command to display on-screen output plotted directly on the model. If de-

sired, the screen graphics can then be printed using the File menu > Print

Graphics command.

The on-screen display data is organized into four data groups, as follows.

Labels

Design Data

Stress Ratios

Deflection Ratios

Each of these data groups is described in more detail later in this Technical

Note. It is important to note that items from different data groups cannot be

displayed simultaneously.

Tip:

The colors related to the beam ratios can be modified by clicking the Options menu >Colors > Output command.

When design information is displayed directly on the model, the frame ele-ments are displayed in a color that indicates the value of their controlling ra-

tio. (Note that this controlling ratio may be a stress ratio or a deflection ra-

tio.) The colors associated with various ranges of ratios are specified in the

Steel Ratios area of the Assign Output Colors form, which is accessed using

the Options menu > Colors > Output command.


45/420

Data Plotted Directly on the Model Composite Beam Design

Technical Note 4 - 2 Labels Displayed on the Model

Labels Displayed on the Model

Beam labels and associated beam design group labels can be displayed on the

model. A beam label is the label that is assigned to the line object that repre-

sents the composite beam.

Tip:

Long labels may not display or print properly (fully).

If a beam has been assigned to a group that has been designated as a com-

posite beam design group, the group name for the beam will be displayed

when requested. If a beam is not part of a composite beam design group, no

group name will be displayed for that beam. Note that you can assign beam

design groups by clicking the Design menu > Composite Beam Design >

Select Design Group command.

As shown in Figure 1, beam labels (B7, B8, etc.) are plotted above or to the

left of the beam, and beam design groups (Group01, Group07, etc.) are dis-

played below or to the right of the beam.

Figure 1: Example of Beam and Design Group Labels

Floor Plan

B7

B8Group01

B9

Group01

B24

Group07

B23

Group08


46/420

Composite Beam Design Data Plotted Directly on the Model

Design Data Technical Note 4 - 3

Tip:

The design data and ratios output that is plotted directly on the model is also available intext form in the short and long form printed output, which are described in AISC-ASD89Composite Beam Design Technical Note 28 Output Details and AISC-LRFD93 Compos-ite Beam Design Technical Note 42 Output Details.

Design Data

The following design data can be displayed on the model:

Beam section (e.g., W18X35)

Beam yield stress, Fy

Shear stud layout

Beam camber

Beam end reactions

One or more of these items can be displayed at the same time. Figure 2

shows an example where all five of these items are displayed. The beam sec-

tion size (e.g., W18X35) is apparent and needs no further explanation.

The beam yield stress is displayed just after the beam section size.

The shear stud layout pattern is displayed in parenthesis just after the beamyield stress. The number of equally spaced shear studs is reported for each

composite beam segment. See Composite Beam Segments in Composite

Beam Design Technical Note 13 Distribution of Shear Studs on a Composite

Beam for more information on composite beam segments.

Important note: It is very important that you fully understand the concept

of composite beam segments. This is necessary to properly interpret the out-

put results for shear studs.

The beam camber is displayed below or to the right of the beam. All other

data is displayed above or to the left of the beam.

The end reactions are displayed at each end of the beam. They are displayed

below or to the right of the beam. The end reactions displayed are the maxi-

mum end reactions obtained from all design load combinations. Note that the


47/420


Technical Note 4 - 4 Stress Ratios

left end reaction and the right end reaction displayed may be from two differ-

ent design load combinations.

Note that cover plate information is not displayed on the model. This infor-mation is available in the printed output (short form or long form; see AISC-

ASD89 Composite Beam Design Technical Note 28 Output Details and AISC-LRFD93

Composite Beam Design Technical Note 42 Output Details) and in the overwrites.

Tip:

The length of the composite beam segments associated with the shear stud layout isdocumented in the short and long form printed output, which are described in AISC-ASD89 Composite Beam Design Technical Note 28 Output Details and AISC-LRFD93Composite Beam Design Technical Note 42 Output Details.

Stress Ratios

The following design data can be displayed on the model:

Construction load bending and shear ratios

Final load bending and shear ratios

Floor Plan

W16X26 Fy=36.00 (14)

W18X35 Fy=36 (22)

W24X55Fy=

50(16,1

6)

C=

0.7

5

W24X55

Fy=50

(16,16)

C=1

.00

W18X35 Fy=36 (48)

C=1.25

16.2 16.2

20.7 20.7

25.2 25.2

23.7

2

3.7

18.4

18.

4 Right reaction

Shear stud layout in

parenthesis

Camber

Beam section

Left reaction

Yield stress

Figure 2: Example of Design Data that Can be Displayed on the Model


48/420

Composite Beam Design Data Plotted Directly on the Model

Deflection Ratios Technical Note 4 - 5

You can display the construction load ratios, the final load ratios, or both.

Bending ratios are always displayed above or to the left of the beam. Shear

ratios are always displayed below or to the right of the beam.

When both construction and final stress ratios are displayed, the construction

load ratios are displayed first, followed by the final load ratios. See Figure 3

for an example.

Deflection Ratios

When the Deflection Ratios option is chosen, the program plots one or both of

the following two ratios.

The maximum live load deflection ratio (live load deflection divided by al-

lowable live load deflection) for deflection loads.

The maximum total load deflection ratio (total load deflection divided by

allowable total load deflection) for deflection loads.

When both ratios are plotted, the live load deflection ratio is plotted first, fol-

lowed by the total load deflection ratio, as shown in Figure 4.

Floor Plan

0.678, 0.961

0.121, 0.245

0.882, 0.978

0.134, 0.222

0.765, 0.994

0.179, 0.311

0.4

67,0

.968

0.135

,0.2

24

0.5

61,

0.9

83

0.2

13,

0.2

93 Construction

load bending

ratio

Final loadbending ratio

Construction

load shearratio

Final load

shear ratio

0.678, 0.961

0.121, 0.245

Legend

Figure 3: Example of Stress Ratios That Are Displayed on the Model


49/420


Technical Note 4 - 6 Deflection Ratios

Floor Plan

0.521, 0.426

0.612, 0.433

0.445, 0.409

0.419,

0.3

26

0.3

92,

0.3

72

Live load

deflection ratio

Total load

deflection ratio

0.521, 0.426

Legend

Figure 4: Example of Deflection Ratios That AreDisplayed on the Model


50/420General Technical Note 5 - 1



Technical Note 5

Input Data

General

This Technical Note describes the composite beam input data that can be

printed to a printer or to a text file when you click the File menu > Print

Tables > Composite Beam Design command. You can print any combina-

tion of five data categories.

Using the Print Composite Beam Design Tables FormTo print composite beam design input data directly to a printer, use the File

menu > Print Tables > Composite Beam Design command and click the

check box on the Print Composite Beam Design Tables form next to the de-

sired type(s) of input data. Click the OK button to send the print to your

printer. Click the Cancel button rather than the OK button to cancel the

print.

Use the File menu > Print Setup command and the Setup>> button to

change printers, if necessary.

To print composite beam design input data to a file, use the File menu >

Print Tables > Composite Beam Design command and click the Print to

File check box on the Print Composite Beam Design Tables form. Click the

Filename>> button to change the path or filename. Use the appropriate file

extension for the desired format (e.g., .txt, .xls, .doc). Click the OK buttons

on the Open File for Printing Tables form and the Print Composite Beam De-

sign Tables form to complete the request.

Note:

The File menu > Display Input/Output Text Files command is useful for displaying out-put that is printed to a text file.

The Append check box allows you to add data to an existing file. The path and

filename of the current file is displayed in the box near the bottom of the Print


51/420

Input Data Composite Beam Design

Technical Note 5 - 2 Material Properties Input Data

Composite Beam Design Tables form. Data will be added to this file. Or use

the Filename>> button to locate another file, and when the Open File for

Printing Tables caution box appears, click Yes to replace the existing file.

If you select a specific composite beam(s) before using the File menu >

Print Tables > Composite Beam Design command, the Selection Only

check box will be checked. The print will be for the selected beam(s) only. If

you uncheck the Selection Only check box, the print will be for all composite

beams.

Material Properties Input Data

The Material Properties input data item prints the concrete and steel material

properties assigned to all frame sections that are the current design section

for a selected composite beam. If no objects are selected, it prints the con-crete and steel material properties assigned to all frame sections that are the

current design section for anycomposite beam.

The material properties printed in this output are those that are used in the

composite beam design. For example, mass per unit volume is not used in the

composite beam design so it is not printed in these tables. Table 1 lists the

column headings in the material property tables and provides a brief descrip-

tion of what is in the columns.

Table 1 Material Properties Input Data

COLUMN HEADING DESCRIPTION

Concrete Material Properties

Material Label Label (name) of the concrete material property.

Modulus of Elasticity Modulus of elasticity, Ec, of the concrete material. Note that thisis the modulus of elasticity used for deflection calculations, butnot necessarily for stress calculations. See "Effective SlabWidth and Transformed Section Properties" in Compos-

ite Beam Design Technical Note 8 Effective Width of theConcrete Slab for more information.

Unit Weight Weight per unit volume of the concrete.

Concrete f'c Compressive strength of the concrete.


52/420

Composite Beam Design Input Data

Section Properties Input Data Technical Note 5 - 3

Table 1 Material Properties Input Data


Steel Material Properties

Material Label Label (name) of the steel material property.

Modulus of Elasticity Modulus of elasticity, Es, of the steel material.

Unit Weight Weight per unit volume of the steel.

Steel Fy Yield stress of the steel.

Steel Fu Minimum tensile strength of the steel.

Steel Price Price per unit weight (e.g., $/pound) of the steel.

Section Properties Input DataThe section properties input data is provided in two tables, labeled Frame

Section Property Data (Table 1) and Frame Section Property Data (Table 2).

This data is provided in two tables because it would not all fit onto one line in

a single table. Table 2 herein lists the column headings in the section property

tables and provides a brief description of what is in the columns.

Table 2 Section Properties Input Data


Frame Section Property Data (Table 1)

Section Label Label (name) of the steel frame section.

Material Label Label (name) of the steel material property that is assigned tothe steel frame section.

bf Top Width of beam top flange.

tf Top Thickness of beam top flange.

d Depth Depth of beam measured from the top of the beam top flange tothe bottom of the beam bottom flange.

tw Web Thick Thickness of beam web.

bf Bottom Width of beam bottom flange.

tf Bottom Thickness of beam bottom flange.


53/420


Technical Note 5 - 4 Deck Properties Input Data

Table 2 Section Properties Input Data


Frame Section Property Data (Table 2)

Section Label Label (name) of the steel frame section.

Material Label Label (name) of the steel material property that is assigned tothe steel frame section.

k In a rolled beam section, the distance from the outside face ofthe flange to the web toe of the fillet.

I33 Major Moment of inertia about the local 3-axis of the beam section.

S33 Major Section modulus about the local 3-axis of the beam section. Ifthe section moduli for the top and bottom of the beam are dif-ferent, the minimum value is printed.

Z33 Major Plastic modulus about the local 3-axis of the beam section. Ifthe plastic moduli for the top and bottom of the beam are differ-ent, the minimum value is printed.

Deck Properties Input Data

The deck properties input data is provided in three tables, labeled Deck Sec-

tion Property Data (Geometry), Deck Section Property Data (Material Proper-

ties), and Deck Section Property Data (Shear Studs). Table 3 lists the column

headings in the deck property tables and provides a brief description of whatis in the columns.

Table 3 Deck Properties Input Data


Deck Section Property Data (Geometry)

Section Label Label (name) of the deck section.

Solid Slab This item is Yes if the deck section represents a solid slab with

no metal deck. Otherwise it is No.

Slab Cover The depth of the concrete slab above the metal deck, tc. If thedeck section represents a solid slab with no metal deck, this isthe thickness of the solid slab.

Deck Depth The height of the metal deck ribs, hr. This item is specified asN/A if the deck section represents a solid slab.


54/420


Deck Properties Input Data Technical Note 5 - 5

Table 3 Deck Properties Input Data


Rib Width The average width of the metal deck ribs, wr. This item is speci-fied as N/A if the deck section represents a solid slab.

Rib Spacing The center-to-center spacing of the metal deck ribs, Sr. Thisitem is specified as N/A if the deck section represents a solidslab.

Deck Section Property Data (Material Properties)


Deck Type This item is either Filled, Unfilled or Solid. Filled means that thedeck section is a metal deck filled with concrete. Unfilled meansit is a bare metal deck. Solid means it is a solid slab with nometal deck.

Slab Material This is the concrete material property associated with the con-crete slab defined by the deck section. If the Deck type is Un-filled, this item is specified as N/A.

Deck Material This is the steel material property associated with the metaldeck. This item is only specified when the Deck Type is Un-filled. If the Deck type is notUnfilled, this item is specified asN/A.

Deck Shear Thickness This is the shear thickness of the metal deck. This item is onlyspecified when the Deck Type is Unfilled. It is used for calcu-

lating the shear (in-plane, membrane) stiffness of the deck. Ifthe Deck type is notUnfilled, this item is specified as N/A.

Deck Unit Weight This is the weight per unit area of the metal deck, wd. See"Metal Deck and Slab Properties" in Composite BeamDesign Technical Note 7 Composite Beam Properties formore information.

Deck Section Property Data (Shear Studs)


Stud Diameter Diameter of the shear studs associated with the deck section,

ds.Stud Height Height after welding of the shear studs associated with the deck

section, Hs.

Stud Fu Minimum specified tensile strength of the shear studs associ-ated with the deck section, Fu.


55/420


Technical Note 5 - 6 Design Preferences Input Data

Design Preferences Input Data

The output for the composite beam design preferences is provided in a series

of tables. The tables correspond to the tabs in the Preferences form. You can

click the Options menu > Preferences > Composite Beam Design com-

mand to access the composite beam preferences.

Note:

The composite beam preferences are described in AISC-ASD89 Composite Beam De-sign Technical Note 17 Preferences and AISC-LRFD93 Composite Beam Design Tech-nical Note 30 Preferences.

Recall that the composite beam preferences apply to all beams designed us-

ing the Composite Beam Design postprocessor. A few of the preference items

can be overwritten on a beam-by-beam basis in the composite beam over-

writes. Those preferences items that can be overwritten are mentioned in this

documentation. You can select one or more beams and then click the Design

menu > Composite Beam Design > View/Revise Overwrites command

to access the composite beam overwrites.

The preference input data is provided in tabular format. Table lists the column

headings in the preference table and provides a brief description of what is in

the columns.

Table 4 Preferences Input Data


Factors

The input data related to factors is described in AISC-ASD89 Composite Beam Design

Technical Note 17 Preferences and AISC-LRFD93 Composite Beam Design Technical

Note 30 Preferences.

Beam Properties

Shored Floor This item is Yes if the composite beam preferences designatethat the composite beams are to be shored. Otherwise, it is No.Note that this item can be modified on a beam-by-beam basisin the composite beam overwrites.


56/420


Design Preferences Input Data Technical Note 5 - 7



Middle Range Length in the middle of the beam over which the programchecks the effective width on each side of the beam, expressed

as a percentage of the total beam length. See "Location WhereEffective Slab Width is Checked" in Composite Beam DesignTechnical Note 8 Effective Width of the Concrete Slab for moreinformation.

Pattern LL Factor Factor applied to live load for special pattern live load check forcantilever back spans and continuous spans. See "Special LiveLoad Patterning for Cantilever Back Spans" and "Special LiveLoad Patterning for Continuous Spans" in Composite BeamDesign Technical Note 10 Design Load Combinations for moreinformation.

Deflection and CamberNote:

Deflection and camber are described in Composite Beam Design TechnicalNote 11 Beam Deflection and Camber.

Live Load Limit Live load deflection limitation. The term L represents the lengthof the beam. Note that this item can be modified on a beam-by-beam basis in the composite beam overwrites.

Total Load Limit Total load deflection limitation. The term L represents the lengthof the beam. Note that this item can be modified on a beam-by-beam basis in the composite beam overwrites.

Camber DL Percent Percentage of dead load (not including superimposed deadload) on which the program camber calculations are based.See "Camber" in Composite Beam Design Technical Note 11Beam Deflection and Camber for more information.

VibrationNote:

Vibration is described in Composite Beam Design Technical Note 12 BeamVibration.

Percent Live Load Percentage of live load plus reduced live load considered (inaddition to full dead load) when computing weight supported bythe beam for use in calculating the first natural frequency of thebeam.


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Technical Note 5 - 8 Beam Overwrites Input Data



Consider Frequency If this item is Yes, the specified minimum acceptable frequencyis considered when selecting the optimum beam section from

an auto select section list. If this item is No, frequency is notconsidered when selecting the optimum beam section.

Minimum Frequency The minimum acceptable first natural frequency for a floorbeam. This item is used when the Consider Frequency item isset to Yes.

Murray Damping If this item is Yes, the Murray's minimum damping requirementis considered when selecting the optimum beam section froman auto select section list. If this item is No, Murray's minimumdamping requirement is not considered when selecting the op-timum beam section. See "Murray's Minimum Damping

Requirement" in Composite Beam Design Technical Note 12Beam Vibration for more information.

Inherent Damping Percentage critical damping that is inherent in the floor system.This item is used when the Murray Damping item is set to Yes.

Price

Consider Price If this item is Yes, the section price rather than steel weight isconsidered when selecting the optimum beam section from anauto select section list. If this item is No, section price is notconsidered when selecting the optimum beam section. The

section price is based on specified prices for steel, shear studs,and camber.

Stud Price Installed price for a single shear stud.

Camber Price Camber price per unit weight of steel beam (including coverplate, if it exists).

Beam Overwrites Input Data

Beam Overwrites Input Data is described in AISC-ASD89 Composite Beam

Design Technical Note 18 Overwrites and AISC-LRFD93 Composite Beam De-

sign Technical Note 31 Overwrites.


58/420Overview Technical Note 6 - 1



Technical Note 6

Output Details

Overview

This Technical Note describes the composite beam output summary that can

be printed to a printer or to a text file. Additionally, both short form and long

form of the output details can be printed. See AISC-ASD89 Composite Beam

Design Technical Note 28 Output Details and AISC-LRFD93 Composite Beam

Design Technical Note 42 Output Details for more information about the

short- and long-form outputs.

Using the Print Composite Beam Design Tables Form

To print composite beam design output data directly to a printer, use the File

menu > Print Tables > Composite Beam Design command and click the

Summary check box on the Print Composite Beam Design Tables form. Also

select the form, or detail, of the print by selecting None, Short Form, or Long

Form. Click the OK button to send the print to your printer. Click the Cancel

button rather than the OK button to cancel the print. Use the File menu >

Print Setup command and the Setup>> button to change printers, if neces-

sary.

Note:

A design must be run before output data can be generated.

To print summary output data to a file, use the File menu > Print Tables >

Composite Beam Design command and click the Print to File check box on

the Print Composite Beam Design Tables form. Click the Filename>> button

to change the path or filename. Use the appropriate file extension for the de-sired format (e.g., .txt, .xls, .doc). Click the OK buttons on the Open File for

Printing Tables form and the Print Composite Beam Design Tables form to

complete the request.


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Output Details Composite Beam Design

Technical Note 6 - 2 Summary of Composite Beam Output

Note:

The File menu > Display Input/Output Text Files command is useful for displaying out-put that is printed to a text file.

The Append check box allows you to add data to an existing file. The path and

filename of the current file is displayed in the box near the bottom of the PrintComposite Beam Design Tables form. Data will be added to this file. Or use

the Filename button to locate another file, and when the Open File for Print-

ing Tables caution box appears, click Yes to replace the existing file.

If you select a specific composite beam(s) before using the File menu >

Print Tables > Composite Beam Design command, the Selection Only

check box will be checked. The print will be for the selected beam(s) only. If

you uncheck the Selection Only check box, the print will be for all composite

beams.

Summary of Composite Beam Output

The summary of composite beam output prints a concise summary of the

composite beam results in a tabular form. One row of the output table is de-

voted to each composite beam.

If you have selected some composite beams before printing the summary

data, only summary data for the selected beams is printed. If you have not

selected any composite beams before printing the summary data, summary

data for all composite beams is printed.

Table 1 lists the column headings in the Summary of Composite Beam Output

table and provides a brief description of what is in the columns.

Table 1 Composite Beam Output Table


Story Level Story level associated with the beam.Beam Label Label associated with the line object that represents the beam.

A typical beam label example is "B23." Do not confuse this withthe Section Label, which may be identified as "W18X35."

Section Name The current design section for the beam.

Beam Fy Yield stress of the beam, Fy.


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Composite Beam Design Output Details

Summary of Composite Beam Output Technical Note 6 - 3

Table 1 Composite Beam Output Table


Stud Diameter Diameter of shear studs, ds.

Stud Layout Number of studs in each composite beam segment separatedby commas. They are listed starting with the composite beamsegment at the I-end of the beam and working toward the J-endof the beam.

Beam Shored This item is Yes if the beam is shored and No if it is unshored.

Beam Camber The camber for the beam. This item may be calculated by theprogram, or it may be user-specified.


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62/420Beam Properties Technical Note 7 - 1



Technical Note 7

Composite Beam Properties

This Technical Note provides an overview of composite beam properties.

Items described include beam properties, metal deck and concrete slab prop-

erties, shear connector properties, user-defined shear connector patterns,

cover plate properties, effective slab width and beam unbraced length.

The many properties associated with composite beams are defined using vari-

ous menus in the program. The steel beam itself is defined using the Define

menu > Frame Sections command. The cover plate, if it exists, is defined inthe composite beam overwrites for the beam. The metal deck, concrete slab

and shear connectors are defined together as part of the Deck section prop-

erties using the Define menu > Wall/Slab/Deck Sections command.

Other items related to the beam properties are specified in the composite

beam preferences or overwrites.

Beam Properties

Figure 1 shows a typical composite beam for reference. The beam shown is a

rolled beam section from the built-in section database.

Tip:

The Composite Beam Design postprocessor only designs beams that are I-shaped sec-tions and channel sections.

Basic steel beam properties are defined using the Define menu > Frame

Sections command. Use this command to define the basic geometry of the

steel section, except for the cover plate, if it exists. Define the cover plate on

the Beam tab in the composite beam overwrites. When defining a beam, a

material property that includes the yield stress for that beam is also assigned.

That yield stress is assumed to apply to the beam and the cover plate unless

it is revised in the beam overwrites. The steel Material Property also includes

the price or cost-per-unit-weight that is assigned to the beam.


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Composite Beam Properties Composite Beam Design

Technical Note 7 - 2 Beam Properties

The beam section for a composite beam can be any I-shaped section, or a

channel. The I-shaped section can be defined by selecting a W, M, S or HPshape from the built-in program steel section database, or by defining your

own I-shaped section using the Define menu > Frame Sections command

and selecting the Add I/Wide Flange option from the drop-down list on the

Define Frame Properties form. It is not necessary that the top and bottom

flanges have the same dimensions in user-defined I-shaped sections used as

composite beams. A channel section used as a composite beam can also be a

section taken from the built-in program steel section database or user-

defined, using the Define menu > Frame Sections command and selecting

the Add Channel option from the drop-down list on the Define Frame Proper-ties form.

Note:

See the section entitled Cover Plates later in this Technical Note for more information.

Figure 1: Illustration of Composite Beam

bcp

hr

tc

d

tcp

Concrete slab

Metal deck

Shear stud

Steel beam

Cover plate

wr

Sr

Hs


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Composite Beam Design Composite Beam Properties

Metal Deck and Slab Properties Technical Note 7 - 3

Beam sections defined using Section Designer are considered as general sec-

tions, not I-shaped or channel-shaped sections (even if they really are I-

shaped or channel-shaped), and cannot be designed using the Composite

Beam Design postprocessor.

If you define a beam section by selecting it from the built-in section database,

the program assumes that it is a rolled section and applies the design equa-

tions accordingly. If you create your own user-defined section, the program

assumes it is a welded section and revises the design equations as necessary.

The program does not check or design any of the welding for these welded

beams.

Metal Deck and Slab Properties

Basic metal deck and concrete slab properties are defined using the Definemenu > Wall/Slab/Deck Sections command. This command specifies the

geometry and the associated material properties of the metal deck, concrete

slab and shear connectors.

Tip:

A beam designed using the Composite Beam Design postprocessor can only have com-posite behavior if it supports a deck section (not a slab or wall section).

Important note: You must specify the concrete slab over metal deck as a

deck section property(not a slab section property) if you want the beam tohave composite behavior. If you specify the slab using a slab section property

instead of a deck section property, the Composite Beam Design postprocessor

designs the beams supporting that slab as noncomposite beams.

Using the Define menu > Wall\Slab\Deck Sections command, select a

deck-type section and click the Modify/Show>> button to bring up the Deck

Section form. This box allows you to specify that the deck section is a Filled

Deck (metal deck filled with concrete), an Unfilled Deck, or a Solid Slab (solid

concrete slab with no meta

Documents

Composite Design Manual (ETAB Ver. 8)