Wardenier “Tubular Structures Course”

1. Examples Hollow Section Trusses Design Procedure Wardenier “Tubular Structures Course”

2. Truss Design Procedure Determine truss layout, span, depth, panel lengths, truss spacing by usual methods.Keep connections to a minimum. Determine loads at connections and on members.Simplify these initially to equivalent loads at panel points. Determine axial forces in all membersby assuming that joints are pinned and assume all member centre lines are noding. 1. 2. 3. Wardenier “Tubular Structures Course”

3. Determine chord member sizes considering: 4. Axial load Corrosion protection (surface area) Wall slenderness Truss Design Procedure Wardenier “Tubular Structures Course”

4. 5. Determine web member sizes considering: Axial load tweb < tchord K = 0.75 for compression webs 6. Standardize the brace member sizes: e.g. to 2 or 3 sizes Same width, different thickness? Inspection problem Check availability! 7. Layout connections: Try gap connections first Check connection geometry is within validity range Check member sizes are within validity range Pay attention to eccentricity limits Consider fabrication procedure Truss Design Procedure Wardenier “Tubular Structures Course”

5. Truss Design Procedure 8. Check connection efficiencies (with charts)or resistances(with formulae or tables) Usually only a few connections need to be checked. If efficiencies or resistances are not adequate, modify the connection layout (e.g. overlap instead of gap), or Modify the members; Re-check connections. 9. Wardenier “Tubular Structures Course”

6. Truss Design Procedure 10. Check effect of primary moments on chord design. Use proper load positions on members Determine member bending moments assuming: Pinned joints everywhere or Continuous chords with pin-ended webs For compression chord, also consider noding eccentricity moment. Check member (axial and bending) interactions. 11. Check truss deflections under specified loads. Design welded joints. Fillet welding cheapest 12. (Note: Weld Design can be left to the fabricator but not connection verification) Wardenier “Tubular Structures Course”

7. Some Golden Rules to Avoid Connection Problems General Tips for Designers Wardenier “Tubular Structures Course”

8. Overlap Joints or braces Gap Joints Deflections of Trusses Check Deflections Under Specified Loads or Wardenier “Tubular Structures Course”

9. Design Example of Design Guide 1 Wardenier “Tubular Structures Course”

10. CHS K joint Wardenier “Tubular Structures Course”

11. Efficiency CHS K joint Wardenier “Tubular Structures Course”

12. Effect Chord Pre-stress Wardenier “Tubular Structures Course”

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15. Note: Gap of joint 2 is decreased to satisfy joint strength and the eccentricity is taken into account for the member check Wardenier “Tubular Structures Course”

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17. Design Example of Design Guide 3 Wardenier “Tubular Structures Course”

18. RHS K joint Wardenier “Tubular Structures Course”

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20. Efficiency RHS K joint Wardenier “Tubular Structures Course”

21. Effect Chord stress Wardenier “Tubular Structures Course”

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