Getting started -portal frame

Model a portal frame in GSA

This tutorial will give you step-by-step instructions on how to model this simple portal frame in GSA and by the end of this tutorial you should be able to:

• Setup a new model with the new model wizard.
• Create the geometry using nodes and 1D members.
• Assign members as columns and beams and mesh the model.
• Add different types of loads.
• Analyse and view results.

Setting up a new model

This tutorial takes you through the setup of a new model using the New model wizard.

Note the settings explained in this section can also be changed later inside the model.

Create a new model

1. Open GSA and select Setup new model. Alternatively, if you already have a model open, go to File > New from the top menu, (or click Ctrl+N) to bring up the New model wizard.

   

2. Name your project and click Next.

3. Set up Units as appropriate then click Next.

Adding codes, grades and sections

You should now see the New model wizard: Properties. Use the drop down fields to select steel and concrete design codes and grades. This tutorial uses the Steel code BS EN 1993-1-1:2005 (GB) and Concrete code BS EN 1993-2:2005 (GB). Select Steel grade as S275 and Concrete grade as C40/50.

Adding a steel catalogue

1. In the properties window, select Steel catalogue > Add.

2. This will bring up the Add catalogue sections dialogue box. The material grade you chose in the previous section will be selected automatically. The analysis material will be set to 'from Grade'.

3. Set the Name to '<d>' (if it is not already) to use the section description as the section name in your model.

4. Select your catalogue, and type, and choose from the drop down options.

5. Then select your section to add.

6. Click OK to add the section.

Note: Hold the Ctrl key to add multiple sections from the catalogue.

This tutorial uses British Steel as the catalogue, Universal Columns (UC) as the type and a section of 203x203x60.

7. You will be taken back to the New model wizard: Properties window. To continue adding catalogue sections, (e.g. for the beam section in the example, adding Universal Beams (UB) > UB 406x178x54) repeat steps 1-6 above.

8. Click Finish to exit the Wizard and start work on your model.

Creating nodes and 1D members

This section describes how to add nodes to your model and create 1D elements by:

• Extruding them from the nodes

• Sketching them in the graphics window

Add support nodes

1. Go to Explorer pane > Data > Nodes to open the nodes data table.

2. Set the first node at (0,0,0).

3. Click the first cell and press the Enter key to copy all default values from the line above:

In the example below, we have entered '10' as the x coordinate for row 2, then hit Enter to copy all subsequent default values.

Tip: To enlarge the font size in the table. Click Ctrl then scroll up using your mouse wheel.

4. In your graphic view, you should now see your nodes on the grid, represented as red dots. Select the Plan tool: or press P to change your plan view:

Setting column type

1. From the Design layer, select the Entities tool: or use the keyboard shortcut Ctrl+Shift+Alt+E

2. This will bring up the Member properties pane.

3. Type E to select members.

4. The property will be set to '1'. The columns you draw will use the first section defined in the section library.

Under the property drop down, the category codes you have just set up will be visible.

Creating columns by extrusion

1. To begin, change the graphic view. Click the Isometric (keyboard shortcut **i**) or **Perspective view** tool (keyboard shortcut k)

2. Click the Nodes selection tool: or use keyboard shortcut n.

3. Drag or click to select the two nodes you have created. They will show as a purple square:

4. In the top menu, go to Sculpt > Extrude selection.

5. In the extrude dialogue box, select your extrusion axis (the default is z).

6. Add the number of increments and increment length.

7. Tick Include 1D members along extrusion:

8. Click Preview to check your elements.

9. Click OK. Columns are displayed in the graphics window.

Inspecting elements in the graphics window

• The Resize to fit tool changes the graphic view:

• From here, you can click and drag the right mouse button to rotate the view.

• The Section display tool gives a 3D view of your columns:

• Use the Select elements/members tool to select a column and view its properties:

• These are displayed in the Messages pane (usually found at the bottom of the graphic window) and Properties pane (typically on the right).

Creating a beam by sculpting

1. Select the Add entities tool: or use keyboard shortcut Ctrl+Shift+Alt+E .

2. Return to the Member property pane. If you have set up a beam, in the property drop down, change the value to '2' to use the beam section.

3. Click on the node at the top of one of your columns. A line representing the beam you are about to draw will appear.

4. Click the node at the top of the other column to complete the beam.

Setting restraints

1. Click the Node select icon: or use keyboard shortcut N

2. Select the nodes at the bottom the columns to display the Nodes properties pane.

3. Go to Restraints > Fix to restrain the nodes.

4. Select the Label restraints tool to show restraints in the graphics window:

Mesh the model

Since we started by modeling the geometry in the Design layer, we'll now need to create the corresponding elements needed for finite element analysis in the Analysis layer. This is needed in order to run the analysis and inspect applied loads, thus we recommend carrying out this step once the model geometry is created.

1. Go to the top menu. Select Model > Coordination tools > Create elements from members or click the following toolbar button:

2. A dialogue box will appear. Set the member list to All, and press OK.

Note: You can now toggle between viewing the members in the Design layer and the analysis elements in the Analysis layer. To toggle between the layers, switch layers. To continue working with members, stay in the Design layer.