Add Structural Stability to a Structure

To add structural stability to a structure requires the insertion of beams to give structural stability. The creation of these beams includes some variations of the ways so far used to define the start and end positions of the beams.

The diagram below gives an example of a structure that requires the addition of beams to give it structural stability.

As a start point, create the three most southerly beams:

1. Create a single beam.

2. Split it into three lengths to fit between the columns, refer to Split a Beam.

3. Create the three beams directly to the north of those which have just been created (shown cross-hatched on the diagram).

   The beams are created in a sequence of operations in which the start of each section (after the first) is situated automatically at the end of the section that precedes it.

4. In the Section window set the String Method to Continuous to create a chained configuration of sections.

   By default, the start of the next section is assumed to be at the end of the previous section (as shown in the 3D View); click Redefine Start to override this.

5. On the Positioning Control toolbar, set the pick method to Intersect to show that positions are to be identified at the intersection points of pairs of sections that already exist.

6. To create the first beam, pick first Column 3 and then Beam 2 (whose intersection is at the Start Position of the first required beam, labelled A in the diagram), then use the same method to pick the intersection which identifies the end of this beam (B in the diagram). If Confirm is selected, click Accept to create the beam.

   It is important to stress the behavior of not picking the attached member first as the sequence of picking the intersections determines the ownership of the SNOD/SJOI and therefore the connectivity model.

   The start of the next beam is positioned automatically at B (as shown in the figure).

7. Use the same procedure to pick points C and D to create the next two beams.

8. Click Redefine Start in the Section window to define a new start for another section or sequence of sections.

9. Add sufficient beams to stabilise the structure with a combination of the techniques described previously. Switch Confirm to Off to speed up the process. To correct a mistake in the middle of defining a section, click Redefine Start to go back a stage.

   Note: You can use the Middle Button Drag view manipulation options available from the 3D View shortcut menu to give a clear view of the correct sections.

10. Click Dismiss to discard any information and close the Section window when the results are satisfactory.

    Note: If the beams are simply copied, either singly or as a composite list, the copies are positioned but are not connected automatically.

11. To update the database so as to store the most recent changes to the structure which has been created, select Design Save Work from the main menu bar or click Save work.