Grillage Structure Properties

(If not continuing from last section, open "EU Example 10_1 Grillage.sst" via Help | Tutorials | Open Tutorial Model... from the main menu.)

1. In the Structure Properties navigation window click on the Create Section and Beam Groups task to create one instance of each of the Design Beams and Design Section previously defined.

2. Select SP3: Inner Beam Span 1 in the navigation tree to open the Structure Properties: Beam form for this Beam Reference.

3. Change Type: to “Transformed section”, and Beam Section Reference Axis Relative to: to “origin”.

4. The concrete beams are to be cracked for 15% of their length either side of the central support, so set the value in the Cracked Section from right/Proportion field to “0.15”.

5. In the graphics window select the four inner beams in the left-hand span.

6. Click on ✓ OK to close the form.

7. Follow similar procedures to those in the previous step to assign the appropriate section properties to the other beams.

8. Click on the Show 3D Elements view icon in the main toolbar to view the elements of the structure in a 3D representation.

   It should be noted that the south edge beams are back to front. This can be corrected by swapping the property assignments and changing the orientation of the longitudinal beams.

   

9. In the Structure Properties navigation window select SP5: Edge Beam Span 1 and then assign this to the south edge beam of span 2 (Yes to overwrite).

10. Also do the same for SP6: Edge Beam Span 2 assigning it to span 1.

11. The direction of beams can be altered in the Structure Definition navigation window by selecting Longitudinal Beams. This opens the Longitudinal Beams form.

12. Select the two southern edge beams (holding the <Ctrl> key for multiple selections) and select “Reverse Order_” in the _Beam Tasks list. The orientation of each beam is denoted by the small red arrow at the end of beam.

13. Click ✓ OK to close the form. Check the 3D Elements view again.

14. In the Structure Properties navigation window select SP2: Nominal to open the Structure Properties: Section form.

15. Assign this section to the longitudinal beam elements at the extreme edges of the deck (leave Section Reference Axis Relative to: as “centroid”) and close the form with ✓ OK.

16. Select SP1: Diaphragm in the navigation window, set the Reference Axis Relative to: field to “origin” and assign this to the beam elements representing the three transverse diaphragms before closing the form.

17. Click on the button and select “Continuous slab” from the dropdown list. This will open the Structure Properties: Continuous Slab form.

18. Change the Depth to “200mm” and Description to “Transverse Slab” and ensure that the Material Property is the grade “32/40 property.

19. Click on the Member selection filter dropdown menu and select “Transverse Beams”.

20. Draw a box around the whole structure and answer “No to All” on the confirmation box that appears. This stops the program form overwriting the diaphragm section assignments.

21. Now remove the filter by clicking on the Member selection filter drop down and selecting “Select All”.

22. Click on ✓ OK to close the form.

23. Click on the 3D Element View icon to view the elements of the structure in a 3D representation. Note that the transverse slab members are incorrectly located at the soffit of the pre-cast beams.

24. In the Structure Definition navigation window, with Refined Model selected, click on the + button and select Advanced Beam Set | Eccentricities form the dropdown list to open the Define Beam Eccentricities form.

25. Click on the + button to add a row in the table and enter a value of “1370” in the Start Z and End Z columns.

26. Apply this eccentricity to the transverse slab members which can be achieved by opening the graphics filter form to first Deselect all and then Select By “Structure Property” where just the “Transverse Slab” property is selected before closing the filter form.

27. Drawing a window round the whole structure will then apply these offsets to just the slab members.

28. Set the filter to “Select All”.

29. For completeness select the 4 edge longitudinal beams and apply the same offset.

30. Close the Beam Eccentricities form with the ✓ OK button.

31. Use the 3D Element viewer to check the outcome of these changes.

    

    Note that the members are now correctly located. Clicking on the Object Browser tab below the Navigation Pane and selecting an element in the graphics window displays detailed information about that element in the space that is normally occupied by the Navigation Pane.

32. Save the file as “My EU Example 10_1 Grillage_Structure_Properties.sst”.