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Practice Workbook This workbook is designed for use in Live instructor-led training and for OnDemand selfstudy. The explanations and demonstrations are provided by the instructor in the classroom, or in the OnDemand eLectures of this course available on the Bentley LEARN Server (learn.bentley.com). This practice workbook is formatted for on-screen viewing using a PDF reader. It is also available as a PDF document in the dataset for this course.
Designing Steel Structures This workbook contains exercises to practice designing steel structures in STAAD.Pro according to the AISC 360 Specification.
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Section 1: Prepare the Model for Design
Section Description In this section, you will learn how to specify all of the design commands in accordance with the AISC 360 LRFD Specification.
Skills Taught
Specifying the Steel Design Code
Assigning the Steel Design Parameters
Invoking the Design Command
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Open a STAAD.Pro Model In this exercise, you will learn how to open a STAAD.Pro model.
1. Open Steel_Design.std in STAAD.Pro in the CONNECT Edition Analytical Modeler.
Before you begin the design process, take a few moments to review the dataset model that was supplied with this course, including the following:
Properties: Notice that this model contains wide flange sections, rectangular HSS sections, steel angles, steel rods and steel plates. Load Combinations: The AISC Public load combination generator was used to create the LRFD load combinations. Analysis: For this model, we will be performing a P-Delta analysis which includes P- and P- effects.
2. Keep this model open for the next exercise.
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Specify the Design Code and Method In this exercise, you will learn how to select the appropriate steel design code and enter the following design parameter:
METHOD: Used to specify with LRFD or ASD design method.
The design method, the analysis commands, and the load combinations should all be coordinated with each other to ensure consistency through the design.
1. Continue with the model from the previous exercise. 2. In the Workflow Page Control, click on the Design page. 3. In the Ribbon toolbar, select the Analysis and Design tab and then click on the Steel icon. 4. In the Steel Design dialog, enter the following parameters:
Current Code: AISC 360-10
5. In the Steel Design dialog, click on the Define Parameters... button. 6. In the Design Parameters dialog, select the METHOD item and enter the following parameter:
Enter Design Method: LRFD
Click on the Add button. Then, click Close.
7. In the Quick Access Toolbar, click on the Save icon.
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Specify the Steel Material Properties In this exercise, you will learn how to assign the following steel design parameter:
FYLD: Used to specify the yield strength of steel.
1. Continue with the model from the previous exercise. 2. In the Ribbon toolbar, select the Geometry tab and then click on the Input Units icon. 3. In the Set Input Units dialog, enter the following parameters:
Length Units: Inch {Millimeter}
Force Units: KiloPound {Newton}
Click OK.
4. In the Steel Design dialog, click on the Define Parameters... button. 5. In the Design Parameters dialog, select the FYLD item and enter the following parameter:
Yield Strength of Steel: 50 ksi {350 N/mm2}
Then, click on the Add button.
6. In the Design Parameters dialog, select the FYLD item and enter the following parameter:
Yield Strength of Steel: 46 ksi {320 N/mm2}
Then, click on the Add button. Then, click Close.
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7. Assign the FYLD 50 parameter following the steps indicated below:
In the Steel Design dialog, highlight the FYLD 50 {FYLD 350} item.
In the Ribbon toolbar, select the Geometry tab and then click on the By Property Name > By Property... icon.
In the Select Geometry By Property dialog, hold down the Ctrl key and highlight the W12X26 property.
In the Steel Design dialog, select the Assign to Selected Beams radio button and then click Assign.
In the STAAD.Pro dialog, click Yes to confirm the assignment.
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8. Assign the FYLD 46 parameter following the steps indicated below:
In the Steel Design dialog, highlight the FYLD 46 {FYLD 320} item.
In the Ribbon toolbar, select the Geometry tab and then click on the By Property Name > By Property... icon.
In the Select Geometry By Property dialog, highlight the HSST6X6X0.375 property. Then, click Close.
In the Steel Design dialog, select the Assign to Selected Beams radio button and then click Assign.
In the STAAD.Pro dialog, click Yes to confirm the assignment.
9. In the Quick Access Toolbar, click on the Save icon.
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Specify the Unsupported Length In this exercise, you will learn how to specify the unsupported length of the top or bottom flanges:
UNB: Used to specify the unsupported length of the beam bottom flange for the calculation of bending capacity.
UNT: Used to specify the unsupported length of the beam top flange for the calculation of bending capacity.
For each parameter, the default member length (node to node distance) will be used unless otherwise specified.
1. Continue with the model from the previous exercise. 2. In the Ribbon toolbar, select the Geometry tab and then click on the Beam Cursor icon. 3. In the View Window, hold down the Ctrl key and click on the members indicated in the figure below:
Compression flanges can experience local buckling or lateral torsional bucking between points of bracing. For this exercise, we will assume that the top flange of the infill beams are braced by a deck/grating system every 12 inches {305 mm} which would resist any type of buckling of the top flanges.
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4. In the Steel Design dialog, click on the Define Parameters... button. 5. In the Design Parameters dialog, select the UNT item and enter the following parameter:
Unsupported Length of Top Flange for Calc. Bending Capacity: 12 in {305 mm}
Then, click on the Assign button. Then, click Close.
6. In the Quick Access Toolbar, click on the Save icon.
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Specify the Slenderness Information In this exercise, you will learn how to specify the K and L factors. To control the calculation of the effective length for flexural torsional bucking, you can use the following two parameters:
KX: Used to specify the effective length factor for flexural torsional buckling.
LX: Used to specify the length for flexural torsional bucking. (Default is the member length, node to node distance.)
To control the slenderness calculations (KL/r), you can use the following two types of parameters:
KY or KZ: Used to specify the K value for the local Y axis (usually the minor axis) or the local Z axis (usually the major axis). LY or LZ: Used to specify the length in the local Y or local Z axis for the slenderness value KL/r. (Default is the member length, node to node distance.)
1. Continue with the model from the previous exercise. 2. In the Ribbon toolbar, select the Geometry tab and then click on the Beam Cursor icon.
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3. In the View Window, hold down the Ctrl key and click on the members indicated in the figure below:
For this exercise, we will assume that the minor axis of the columns are unbraced for the entire length of the columns. To ensure that the bracing is considered correctly, we will specify an unbraced length for the minor axis as the length of the columns.
4. In the Steel Design dialog, click on the Define Parameters... button. 5. In the Design Parameters dialog, select the LY item and then enter the following information:
Length in local Y axis for Slenderness Value KL/r: 213 inches {5410 mm}
Then, click Assign, followed by Close.
6. In the Quick Access Toolbar, click on the Save icon.
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Specify the Track Parameter In this exercise, you will learn how to specify the track parameter as follows:
TRACK: Used to control the level of detail to which the results are reported.
1. Continue with the model from the previous exercise. 2. In the Steel Design dialog, click on the Define Parameters... button. 3. In the Design Parameters dialog, select the TRACK item and then enter the following information:
Track Parameter: 1 = Print the Design Output at Intermediate Detail Level
Then, click Add, followed by Close.
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4. Assign the TRACK parameter following the steps indicated below:
In the Steel Design dialog, highlight the TRACK 1 item.
In the Ribbon toolbar, select the Geometry tab and then click on the By Property Name > By Property... icon.
In the Select Geometry By Property dialog, hold down the Ctrl key and highlight the W12X26 property, HSST6X6X0.375 property, and L12012022 property.
In the Steel Design dialog, select the Assign to Selected Beams radio button and then click Assign.
In the STAAD.Pro dialog, click Yes to confirm the assignment.
5. In the Quick Access Toolbar, click on the Save icon.
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Add the CHECK CODE Command Learn how to apply the following command in STAAD.Pro:
CHECK CODE command
The CHECK CODE command instructs STAAD.Pro to check whether the provided section properties of the members are adequate.
1. Continue with the model from the previous exercise. 2. In the Steel Design dialog, click on the Commands... button. 3. In the Design Commands dialog, highlight the CHECK CODE option and click Add. Then, click Close.
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4. Assign the CHECK CODE command following the steps indicated below:
In the Steel Design dialog, highlight the CHECK CODE item.
In the Ribbon toolbar, select the Geometry tab and then click on the By Property Name > By Property... icon.
In the Select Geometry By Property dialog, hold down the Ctrl key and highlight the W12X26 property, HSST6X6X0.375 property, and L12012022 property.
In the Steel Design dialog, select the Assign to Selected Beams radio button and then click Assign.
In the STAAD.Pro dialog, click Yes to confirm the assignment.
5. In the Quick Access Toolbar, click on the Save icon.
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Section 3: Design the Model
Section Description In this section, you will learn how to perform a code check on the steel members and review the design results.
Skills Taught
Performing the Analysis/Design
Reviewing the Results in the Output File
Reviewing the Results in the Post Processor
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Design the Model In this exercise, you will learn how to perform an analysis/design in STAAD.Pro using the following command:
Analyze > Run Analysis...
The Run Analysis commands performs the STAAD analysis as directed by the input commands.
1. Continue with the model from the previous exercise. 2. In the Ribbon toolbar, select the Analysis and Design tab and then click on the Run Analysis icon. 3. Keep the STAAD Analysis and Design dialog open for the next exercise.
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Review the Results in the Output File In this exercise, you will learn how to review the results in the STAAD Output File, which can be accessed after the analysis is complete:
File > View > Output File > STAAD Output
During the analysis/design, the STAAAD Output file will be automatically generated. This file will contain selected input data items, results and error messages.
1. Continue with the model from the previous exercise. 2. In the STAAD Analysis and Design dialog, select the View Output File radio button. Then, click Done. 3. In the Output File, select the RESULTS tab and select the STEEL DESIGN item.
This section contains the results of the CHECK CODE command. This command checked the strength of each member according to the code requirements of the AISC 360-10 LRFD specification.
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4. In the toolbar, click on the Find icon. 5. In the Search dialog, enter the following information:
Fine What: Fail
Then, click on the Fine Next button.
In the Output File, the Find command can be used to quickly access information, such as searching for failing members.
HINT: Click on the Mark All button to locate every Failed member.
6. In the Search dialog, click on the Cancel button. 7. In the Output File, click File > Exit to return to the STAAD.Pro Modeling Mode. 8. In the Quick Access Toolbar, click on the Save icon.
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Review the Analysis Results In this exercise, you will learn how to review the following analysis results in the Post-Processor:
Node Analysis Results: Provides nodal displacement and reaction information (both graphically and in tabular format).
Beam Analysis Results: Provides member forces, stresses, and graphs (both graphically and in tabular format).
1. Continue with the model from the previous exercise. 2. In the Workflow Panel, click Post Processing icon. 3. In the Results Setup dialog, select the Result View Options tab and then click OK.
Enable Automatic Scaling: (checked)
Displacement/Deflection: (checked)
Then, click OK.
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4. In the Workflow Page Control, click on the Displacement page.
The Displacement Diagram shows the displaced shape of the structure according to the currently selected load case. In the Data Area, the following tables provide numerical results for the displacement of the structure:
Node Displacements Table: Used to view numerical values of nodal displacements. Beam Relative Displacement Detail Table: Used to view numerical values for sectional displacements along the length of each member.
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5. In the Workflow Page Control, click on the Beam Results page.
The Beam Force Diagram shows the member force diagrams according to the currently selected load case. STAAD.Pro has preformed a design on all of the AISC standard sections that were assigned in this model. The steel rods were not included in the design. To design them by hand, you can used the Beam Results to obtain the forces that the rods must resist. In the Data Area, the following tables provide numerical results for the displacement of the structure:
Beam End Forces Table: Used to display numerical values for the member end forces.
Beam Force Detail Table: Used to display the cross sectional forces and moments at section along each member.
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6. In the Ribbon toolbar, select the View tab and then click on the Label Settings icon. 7. In the Diagrams dialog, click on the Loads and Results tab. From this area, you can customize the forces that are displayed on screen including axial loads, shear, ad bending.
Click on the Cancel button to close this dialog.
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Review the Beam Design Results In this exercise, you will learn how to review the beam design results in the Post-Processor:
Unity Check: Displays the utilization ratio for each member that is designed.
1. Continue with the model from the previous exercise. 2. In the Workflow Page Control, click on the Beam Results page. 3. In the Ribbon toolbar, select the Layouts > Utilization icon. 4. In the Ribbon toolbar, select the View tab and then click on the Label Settings icon.
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5. In the Diagrams dialog, select the Design Results tab and review the following parameters in the Actual Ratio table:
Grey: Not Designed
Green: From 0 to 1.0
Blue: From 1.0 to 1.5
Red: > 1.5
Then, click OK. The Design Results tab in the Diagrams dialog indicate the four categories of design results:
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Not Designed
Pass (Green)
Fail (Blue)
Extreme Fail (Red)
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6. Identify the Failed Members:
In the Design Results dialog, click on the Failed Members tab.
In the Ribbon toolbar, select the Results tab and then click on the By Property Name > Failed Beams icon. In STAAD.Pro, it is important to understand the Pass/Fail categories and how to identify the failing members:
Calculation Engine: A Fail status will be reported on any member whose unity check value exceeds the maximum allowable interaction ratio (default is 1.0). Post-Processor GUI: The Failed Members tab and the Failed Member Selection command is based on the Fail range (blue or red) defined in the Basic Diagram section of the Design Results tab of the Diagrams dialog.
Note: Several girders, columns, and braces are currently failing. We will now return to the Modeling Mode and assign new sizes to the failing members. After any sizes are changed, the model must be re-analyzed to verify if the new sizes pass the code check.
7. In the Quick Access Toolbar, click on the Save icon.
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Modify the Original Design In this exercise, you will learn how to return to the STAAD Modeling Mode and modify the original section properties.
Note: For this training, we are using the CHECK CODE command, which instructs STAAD.Pro to check whether the provided section properties of the members are adequate. For this approach, we will use trial-and-error until we achieve passing results for all steel members.
1. Continue with the model from the previous exercise. 2. In the Workflow Panel, click Analytical Modeling icon. 3. In the Page Control Area, click on the General tab and the Property sub-tab. 4. Change the size of the steel columns from HSST6X6X0.375 to HSST10X10X0.625:
In the Properties dialog, highlight the HSST6X6X0.375 section and then click on the Edit... button.
In the American Steel Table dialog, select the HSST10X10X0.625 section and then click Change.
In the STAAD dialog, click Yes to confirm the change.
In the American Steel Table dialog, click on the Close button.
5. Change the size of the steel girders from W12X26 to W16X40:
In the Properties dialog, highlight the W12X26 section and then click on the Edit... button.
In the American Steel Table dialog, select the W16X40 section and then click Change.
In the American Steel Table dialog, click on the Close button.
6. In the Quick Access Toolbar, click on the Save icon.
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Verify the Results In this exercise, you will learn how to reanalyze the model and review the results.
1. Continue with the model from the previous exercise. 2. In the Ribbon toolbar, select the Analysis and Design tab and then click on the Run Analysis icon. 3. In the Warning dialog, click on the Save button to continue. 4. In the STAAD Analysis and Design dialog, select the Go to Post Processing Mode radio button. Then, click Done. 5. In the Results Setup dialog, select the Result View Options tab and enter the following information:
Enable Automatic Scaling: (checked)
Displacement/Deflection: (checked)
Then, click OK.
6. In the Workflow Page Control, click on the Beam Results page.
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7. In the Ribbon toolbar, select the Layouts > Utilization icon.
Notice that all of the steel beams, columns, and braces are now passing the unity checks. At this point in your work-flow, you can go back and review the rest of the information in the PostProcessor (such as beam end reactions or nodal displacements).
8. In the Quick Access Toolbar, click on the Save icon.
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