Create a Single Beam

If required, modify the Profile Specification or retain the default specification, for further information refer to Set the Default Specification for Profiles.

1. From the main menu bar select Create > Sections > Straight to redisplay the Section window and the Positioning Control toolbar, which are used to identify positions by picking them with the pointer in the 3D graphical view.

2. Set the String Method to Single to specify the start and end points independently for each section.

3. Select the Secondary Nodes checkbox so that secondary nodes and joints are created automatically at all connections between sections.

4. Select the Confirm checkbox.

5. When it is no longer required, click to clear the Confirm checkbox.

   Note: The Secondary Joint (SJOI) element forms the basis of the analytical model.

   Instead of the use of enter explicit coordinates, the Start Position is defined as a point on one of the columns that already exists which is picked with the pointer.

6. On the Positioning Control toolbar, set the Pick Type option (right-hand drop-down list) to Element. From here you have to pick sections themselves, rather than individual plines, to identify positions within the design model.

7. The Pick Method setting (right-hand drop-down list) specifies how the pointer picks the positions. Set to Snap, this means you wish to snap to the position of the nearest Start or End of a picked section. The option remains in force until you change it.

   You are prompted to ‘Define section start (Snap)’.

8. Pick a point anywhere in the upper half of the column.

   The word Start is displayed in the view to mark the specified start point and the snap action has placed this at the upper end of the column.

   You are then prompted to ‘Define section end (Snap)’.

9. Pick a point anywhere in the upper half of the next column to define the End Position of the new beam.

   Note: The proposed route of the new beam is shown in the 3D View.

10. Click Accept in the Section window to confirm the section creation.

    Beam 1 is shown with its start connected to the top of one column and its end connected to the top of the next column.

The length of the beam is calculated automatically, with allowances for the section dimensions, but the beam’s position is too high. The beam’s position is too high because the justification datum is set to the Neutral Axis (NA), as shown by the Profile Specification setting /BS-SPEC/305x165x40kg/m (NA/NA/NA). The position must now be corrected by resetting the justification datum to the Top of Steel (TOS) pline. The result is as shown in the diagram:

11. Select Navigate to Element from the main menu toolbar to switch temporarily from event-driven graphics mode to graphical navigation mode (check the pick mode prompt).

12. Change the view direction to View > Look > East in the main menu bar.

13. Move the centre of interest to the approximate mid-point of the first beam and zoom in to see more clearly what happens at the ends of the beam.

14. Pick the new beam to make sure that it is the current element and select Modify > Sections > Specification in the main menu bar.

15. In the Section Specification window, set the Justification to TOS, as shown:

    

16. Select the Use as default profile checkbox, so that when the beams are created they are all aligned correctly without further adjustment.

17. Apply the change.

    The beam moves down to the correct position.

    Note: The default specification has changed:

    

18. Alternatively, select the Modify > Sections > Justification option in the main menu bar to realign just the current beam.

You must now create another beam, with its start position at the top of a column, which runs horizontally to connect part-way up the next column. Reset the view, if necessary, to show all sections so far created.

19. Click Dismiss to discard any information and close the Section window to return to event-driven graphics mode.

20. Select Create > Sections > Straight from the main menu bar to position the start of the next Section (check the pick mode prompt again).

21. Position the Start for the beam at the top of the column.

22. To pick the end position, use the snap facility with a specified offset distance along the picked Section.

23. From the Positioning Control toolbar’s Pick Method list, select Distance.

24. In the adjacent Method Value field, enter the height of the end position column (for example, 5000) and press Enter.

    

    You are prompted to ’Pick section end (Distance [5000])’.

25. Pick anywhere in the lower half of end position column. To calculate the End Position snap to the bottom of the column and then move up (that is towards the pointer) by 5000mm.

26. To accept the section, click Accept in the Section window.