How do I change a single span beam into a multi-span beam?

When you model a beam in Tekla Structural Designer you need to keep in mind that you are defining the beam and its physical support points. You therefore need to place the beam and also assign any support locations at the same time.

1. Is this beam correctly modelled as a continuous beam?

 

You can use Scene Content to show the element Direction arrow on the Members

 

Notice that this beam only has one element direction arrow displayed at the centre point of the beam (drawn from End 1 - start to End 2 - finish). This tells us that the beam has only one span and therefore is supported at columns A/1 and D/1 only.

 

You can verify this by right clicking the beam > Edit... and reviewing the Size or Releases page. Multiple spans are not referenced within the dialog so it is a single span beam.

 

 

Another way to determine the number of spans is to review the number of solid blue nodes on the beam. An element span will always have three solid blue nodes. The support points at each end of the element and a p-delta node at the mid-point.

You can review these by selecting the element.

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Note: It is possible to pick up these points. If you pick up an end point you can move the support point of the beam. If you click on the middle node, you can introduce a new support point somewhere along the beam. We will look at this later.

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2. Creating a continuous beam at the time of insertion

At the time of insertion the most efficient way to place a continuous beam would be to use the Continuous option in the Properties window.

By using this you can click on a support point and carry-on with the next span. To finish placing a continuous beam either press Enter after the final support point or click on the end support point again.

 

Notice this beam has three spans as there are three element direction arrows - one for each span

 

Notice the solid blue nodes - three for each span.

 

Hovering over the beam highlights the physical continuous beam.

 

3. Making a single beam a continuous beam

If we return to the screenshot shown earlier, where we had a single beam spanning from A/1 to D/1. What if we wanted to turn this into a continuous beam without having to delete and re-create?

 

Hover over the middle node and using the Select Entity tooltip will pick the option New node on... Click to create a new node on the beam and move the mouse away from the beam.

 

This is a new support point currently defined where the cursor is located.

 

Click on the node at the top of the column to place this new support. Notice the blue sold nodes and the element direction arrow within each beam span.

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The solid node above the column at C/1 is the p-delta node at the middle of the second span

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Repeat for the final span.

4. Joining single beams to form a continuous beam

The screenshot below appears correct, but if you hover over the beam it only highlights one beam and not all the spans. This indicates that each beam is a separate individual beam.

 

You can use the Edit ribbon tab > Join command to join two beams together provided the web of the beam lies in the same plane.

  

Hover over a beam and it provides an indication of the beam it will join to. Click to join the two beams together and then press Esc to exit the command.

 

Hovering over the beam then shows both spans highlighted at the same time.

 

After repeating to join the beam between gridline C/1 and D/1 we can review and confirm the Property - Size and Releases pages

 

Notice the support condition at the internal column - continuous.

 

5. Separating a continuous beam into separate beams

If you wanted to separate a beam you could do this via the Edit ribbon tab > Split command.

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Note: The beam must already be continuous to use this command.

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Click the beam you wish to split and then press Esc. to exit the command

 

Hovering over the beams then shows they have been separated.