Computers and Structures, Inc.
Berkeley, California, USA
January 2002Version 8ETABS
®
Integrated Building Design Software
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
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copyrighted products. Worldwide rights of ownership rest with Computers and
Structures, Inc. Unlicensed use of the program or reproduction of the documentation in
any form, without prior written authorization from Computers and Structures, Inc., is
explicitly prohibited.
Further information and copies of this documentation may be obtained from:
Computers and Structures, Inc.
1995 University Avenue
Berkeley, California 94704 USA
Phone: (510) 845-2177
FAX: (510) 845-4096
e-mail: [email protected] (for general questions)
e-mail: [email protected] (for technical support questions)
DISCLAIMER
CONSIDERABLE TIME, EFFORT AND EXPENSE HAVE GONE INTO THE
DEVELOPMENT AND DOCUMENTATION OF ETABS. THE PROGRAM HAS
BEEN 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.
THIS PROGRAM IS A VERY PRACTICAL TOOL FOR THE DESIGN/CHECK OF
STEEL STRUCTURES. HOWEVER, THE USER MUST THOROUGHLY READ THE
MANUAL AND CLEARLY RECOGNIZE THE ASPECTS OF COMPOSITE DESIGN
THAT THE PROGRAM ALGORITHMS DO NOT ADDRESS.
THE USER MUST EXPLICITLY UNDERSTAND THE ASSUMPTIONS OF THE
PROGRAM AND MUST INDEPENDENTLY VERIFY THE RESULTS.
i
©COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA DECEMBER 2001C
OMPOSITEB
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ESIGNContents
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
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 6-1
Summary 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 Slab
Location 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
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 11-1
Camber 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 12-6
References 12-7
13 Distribution of Shear Studs on a Composite Beam
Overview 13-1
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
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 18-4
Bracing (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 Checks Overview 19-1
Limiting Width-to-Thickness Ratios for
Flanges 19-2
Compact Section Limits for Flanges 19-2
Noncompact Section Limits for
vi
Limiting Width-to-Thickness Ratios
for Webs 19-3
Compact Section Limits for Webs 19-3
Noncompact Section Limits for Webs 19-3 Limiting Width-to-Thickness Ratios for
Cover Plates 19-4
Compact Section Limits for Cover
Plates 19-5
Noncompact Section Limits for Cover
Plates 19-5
20 Transformed Section Moment of Inertia
Background 20-2
Properties of Steel Beam (Plus Cover
Plate) Alone 20-4
Properties of the Composite Section
General Calculation Method 20-7
Equivalent Hand Calculation Method to
Calculate the Distance ye 20-10
Background Equations 20-11
Hand Calculation Process for ye 20-17
Equivalent Hand Calculation Method to
Calculate the Composite Properties 20-18
21 Elastic Stresses with Partial Composite Connection
Effective Moment of Inertia for Partial
Composite Connection 21-1
Effective Section Modulus Referred
to the Extreme Tension Fiber 21-2
Location of the ENA for Partial
Composite Connection 21-3
Steel Section Stresses for Partial
Composite Connection 21-5
Concrete Slab Stresses for Partial
Composite Connection 21-6
22 Allowable Bending Stresses
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 25-1
Shear 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 with Maximum Moment and the
Point of Zero Moment 25-6
Between Other Output Stations and
viii
26 Calculation of the Number of Shear Studs
Basic Equations 26-1
Shear Stud Distribution Example 1 26-4
Shear Stud Distribution Example 2 26-8
Shear Stud Distribution Example 3 26-13
Detailed Calculations 26-15
27 Input Data
Beam Overwrites Input Data 27-1
28 Output Details
Short Form Output Details 28-1
Composite Beam Design Specific to AISC-LRFD93
29 General and Notation
AISC-LRFD93 Design Methodology 29-1
Notation 29-7
30 Preferences
General 30-1
Using the Preferences Form 30-1
Preferences 30-2 Factors Tab 30-3 Beam Tab 30-4 Deflection Tab 30-5 Vibration Tab 30-5 Price Tab 30-6 31 Overwrites General 31-1
Using the Composite Beam Overwrites
Form 31-2 Resetting Composite Beam
Overwrites to Default Values 31-3
Overwrites 31-3
Beam Tab 31-4
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
Limiting Width-to-Thickness Ratios for
Flanges 33-2
Compact Section Limits for Flanges 33-2
Noncompact Section Limits for
Flanges 33-2
Limiting Width-to-Thickness Ratios for
Webs 33-3
Compact Section Limits for Webs 33-3
Noncompact Section Limits for Webs 33-4 Limiting Width-to-Thickness Ratios for
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 34-1
Location 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
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
AISC-FLRD93 Equation A-F1-3 for
FLB 36-9
AISC-FLRD93 Equation A-F1-1 for
LTB 36-9
AISC-FLRD93 Equation A-F1-2 for
LTB 36-10
Moment Capacity for a Singly Symmetric
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 39-1
Number 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 40-2
Limitations of Beam Shear Check 40-2
41 Input Data
xii
42 Output Details
Short Form Output Details 42-1
Design Codes Technical Note 1 - 1
©COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA DECEMBER 2001
C
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ESIGNTechnical 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 "on the fly."
Beams Designed as Composite Beams
Section 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
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 composite beams.
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 must be 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 between supports 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
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 dede-sign procedure. All steel sections that
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 Dede-sign, 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 noncomposite designs 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.
Composite Beam Design General Design Information
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 smallest section 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 the shorter 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
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 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 aquate for all of the beams in the design group, the program proceeds to de-sign each beam in the dede-sign 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, not price.
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.
Composite Beam Design General Design Information
Using Price to Select Optimum Beam Sections Technical Note 1 - 7
You can request that the program use price to determine the optimum section by clicking the Options menu > Preferences > Composite Beam Design command, selecting the Price tab and setting the "Optimize for Price" item to Yes. If you request a price analysis, the program compares alternate accept-able beam designs based on their price and selects the one with the least cost as the optimum section.
For the cost comparison, specify costs for steel, shear studs and beam cam-ber. The steel cost is specified as a part of the steel material property using the Define menu > Material Properties command. The shear stud and beam camber costs are specified in the composite beam preferences.
The costs for steel and cambering are specified on a unit weight of the beam basis; for example, a cost per pound of the beam. The shear connector cost is specified on a cost per connector. By assigning different prices for steel, shear
Important Note about Optimizing Beams by Weight and Price
When a beam is optimized by weight, the program internally optimizes the beam based on area of steel (excluding the cover plate, if it exists). Thus, the weight density specified for the steel is irrelevant in such a case.
When a beam is optimized by price, the program determines the price as-sociated with the steel by multiplying the volume of the beam (including the cover plate, if it exists) by the weight density of the beam by the price per unit weight specified in the material properties for the steel. The price associated with camber is determined by multiplying the volume of the beam (including the cover plate, if it exists) by the weight density of the beam by the specified price per unit weight for camber defined in the com-posite beam preferences. The price for shear connectors is determined by multiplying the total number of shear connectors by the price per connec-tor specified in the composite beam preferences. The total price for the beam is determined by summing the prices for the steel, camber and shear connectors. Thus, when a beam is optimized by price, the weight density for the steel is important and must be correctly specified for the price to be correctly calculated.
Note that the volume of the beam is calculated by multiplying the area of the steel beam (plus the area of the cover plate, if used) by the length of the beam from center-of-support to center-of-support
Technical Note 1 - 8 Design Load Combinations connectors and camber, you can influence the choice of optimum section. The cost of the cover plate is not included in the comparison (but it would be the same for all beam sections if it were included).
See the previous "Important Note about Optimizing Beams by Weight and Price" for additional information.
Design Load Combinations
Using the Composite Beam Design postprocessor, three separate types of load combinations are considered. They are:
Construction load strength design load combinations Final condition strength design load combinations Final condition deflection design load combinations
You can specify as many load combinations as you want for each of these types. In addition, the program creates special live load patterns for cantile-ver beams. See Composite Beam Design Technical Note 20 Design Load binations for additional information on design load combinations for the Com-posite Beam Design postprocessor.
Analysis Sections and Design Sections
Analysis sections are those section properties used to analyze the model when you click the Analyze menu > Run Analysis command. The design section is whatever section has most currently been designed and thus desig-nated the current design section.
Tip:
It is important to understand the difference between analysis sections and design sec-tions.
It is possible for the last used analysis section and the current design section to be different. For example, you may have run your analysis using a W18X35 beam and then found in the design that a W16X31 beam worked. In that case, the last used analysis section is the W18X35 and the current design section is the W16X31. Before you complete the design process, verify that the last used analysis section and the current design section are the same.
Composite Beam Design General Design Information
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.
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 and at 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.
Design Process for a New Building Technical Note 2 - 1
©COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA DECEMBER 2001
C
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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 Building
The 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
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 deDe-sign 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.
Composite Beam Design Composite Beam Design Process
Design Process for a New Building Technical Note 2 - 3
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 selected beams. 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.
d. Use the Design menu > Composite Beam Design > Verify all
Members Passed command to verify that no members are
over-stressed or otherwise unacceptable.
9. Use the Design menu > Composite Beam Design > Change Design
Section command to change the beam design section properties for
se-lected beams.
10. 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 in Step 8.
11. 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.
12. Click the Design menu > Composite Beam Design > Start
De-sign/Check of Structure command to rerun the composite beam design
with the new analysis results and new section properties. Review the re-sults using the procedures described in Step 8.
13. Again use the Design menu > Composite Beam Design > Change
Design Section command to change the beam design section properties
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 analysis and 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 sese-lected 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. See AISC-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
Composite Beam Design Composite Beam Design Process
Check Process for an Existing Building Technical Note 2 - 5
for a new building because iteration is not required. Note that although the sequence of steps you follow may vary, the basic process probably will be es-sentially the same.
Tip:
You can define your own shear stud patterns on the Shear Studs tab in the composite beam overwrites. This allows you to model existing structures with composite floor fram-ing.
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 preferprefer-ences unless you want to change some of the default preference values. See AISC-ASD89 Compos-ite Beam Design Technical Note 17 Preferences and AISC-LRFD93 Com-posite Beam Design Technical Note 30 Preferences for more information about preferences.
2. Create the building model, as explained in Volumes 1 and 2.
3. Run the building analysis using the Analyze menu > Run Analysis command.
4. Assign composite beam overwrites, including the user-defined shear stud patterns, using the Design menu > Composite Beam Design >
View/Revise Overwrites command. Note that you must select beams
first before using this command. See AISC-ASD89 Composite Beam De-sign Technical Note 18 Overwrites and See AISC-LRFD93 Composite Beam Design Technical Note 31 Overwrites.
5. Click the Design menu > Composite Beam Design > Start
De-sign/Check of Structure command to run the composite beam design.
6. Review the composite beam design results by doing do one of the follow-ing:
a. Click the Design menu > Composite Beam Design > Display
De-sign Info command to display deDe-sign input and output information on
the model. See Composite Beam Design Technical Note 4 Data Plotted Directly on the Model.
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 selected beams.
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.
Member Identification Technical Note 3 - 1
©COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA DECEMBER 2001
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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 displayed in the active window. If design results are not displayed (and the design has been run), click the
De-sign menu > Composite Beam DeDe-sign > 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 Identification
Story 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
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 Information
Auto 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.
You cannot directly edit the contents of this list box.
Last Analysis
This list box displays the name of the section that was used for this beam in the 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 secsec-tion property should be the same. You cannot directly edit the contents of this list box.
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 the program as the section property for the next analysis run.
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 of the 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.
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 secSec-tions considered were acceptable.
ReDefine
Sections 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 Secsec-tions 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 the overwrites.
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-Composite Beam Design Interactive Composite Beam Design
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 Button
Click this button to access and make temporary revisions 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 Details
Diagrams 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 Button
Clicking 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.
Technical Note 3 - 6 Show Details
Note:
Stud Details Information is available using the Details button, but is not included in the short 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 in AISC-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, the information 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
Composite Beam Design Interactive Composite Beam Design
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 composcompos-ite beam seg-ments used by the program. See "Composite Beam Segseg-ments" in Composite Beam Design Technical Note 13 Distribution of Shear Studs on a Beam for a definition 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.
Overview Technical Note 4 - 1
©COMPUTERS AND STRUCTURES, INC., BERKELEY, CALIFORNIA DECEMBER 2001
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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 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.
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
B8
Group01
B9
Group01
B2
4
Gr
ou
p0
7
B2
3
Gr
ou
p0
8
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 in text form in the short and long form printed output, which are described in AISC-ASD89 Composite 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 explanasec-tion.
The beam yield stress is displayed just after the beam section size.
The shear stud layout pattern is displayed in parenthesis just after the beam yield 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
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 is documented in the short and long form printed output, which are described in AISC-ASD89 Composite Beam Design Technical Note 28 Output Details and AISC-LRFD93 Composite 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) W 24 X 55 F y= 50 (16 ,16 ) C = 0. 75 W24 X55 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 23 .7 18.4 18.4 Right reaction Shear stud layout in parenthesis Camber Beam section Left reaction Yield stressComposite 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 0.46 7, 0. 968 0.13 5, 0. 224 0. 56 1, 0. 983 0. 21 3, 0.293 Constructionload bending ratio Final load bending ratio Construction load shear ratio Final load shear ratio 0.678, 0.961 0.121, 0.245
Legend
Technical Note 4 - 6 Deflection Ratios
Floor Plan
0.521, 0.426 0.612, 0.433 0.445, 0.409 0.419, 0.326 0. 392, 0. 372 Live load deflection ratio Total load deflection ratio 0.521, 0.426Legend
Figure 4: Example of Deflection Ratios That Are
Displayed on the Model
General Technical Note 5 - 1
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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 Form
To 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
