Technical Training Basics: What is truss

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Technical TrainingBasics What is truss
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Goal of this workshop

• Share knowledge
• Actively promote safe working practices
• Provide product expertise for users

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Topics

• What is truss
• Different forces on Truss
• Analising loading of truss structures
• Truss standards
• Questions

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What is truss ?

• Lattice structure
• Made of (mainly) aluminium tubes
• Low self weight (easy to handle )
• Modular (easy to transport)
• Flexible (lego system)

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What is a lattice structure?

• A lattice structure is an open triangular
  structure.
• Triangular shapes are stable in hinged
  connections
• Triangulation is essential for strength and
  stability

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Similarity between a lattice structure and a
Truss?
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The Truss
Cross bracing
bracing
End bracing
Main tube
Coupling system
Node point
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Why is Truss made of (mainly) aluminium?

• Advantages of aluminium
• /- 1/3 of the weight of steel
• Non corrosive
• Available in large quantities
• Easy to machine
• Allowable stress for tension and compression is
  the same

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Why is Truss made of (mainly) aluminium?

• Disadvantages of aluminium
• Strength decreases after welding with /- 50
• Less stiff as steel
• More difficult to weld
• More expensive

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Main advantage of a Truss structure Low self
weight in relation to a high load bearing
capacity. Achieved by.. Bringing the material to
the position where you need it !!!!!
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Example.
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Different types of coupling systems

• Tube coupler
• Gusset / Endplate
• Hinge connection Male / Female
• Conical coupler

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1 Tube connection-Very high bearing stress in
the main chord-Open space between main chord.
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2 Gusset / Endplate-Bending force in gusset
Plate-Open space between main chord
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3 Hinge connection Male / Female-Fixed
Male/Female sides wear given extra deflexion
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4 Conical coupler-Wear is compensated bij
spigot shape
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Mounting different brands of truss together.

• Although the truss looks the same each type of
  truss has different technical specifications
• Calculation of the system with different
  specifications.
• Responsibility

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• Different forces on Truss
• Loading Forces
• Internal reaction Forces

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Different types of loading

• Point load
• Multiple point load
• Concentrated load
• Uniformly distributed load
• Cantilever load
• Normal force

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• Point load

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• Multiple point load

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• Concentrated load

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• Distributed load

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• Cantilever load

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• Normal Force

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• Internal reaction forces in the Truss
• Bending moment
• Transversal forces ( also known as shear force )
• Normal forces
• Torsion force
• The reaction of these forces is
• Deflection

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• This figure indicates where the internal forces
  are active in the truss.

Normal force
Shear force
Normal force
Bending moment
Normal force
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• Bending moment
• To strain under tension, causing a straight
• line structure to turn into a curve-shape

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• Examples of situations when a bending moment
  occurs
• Self weight caused by the Force of gravity
• Live loading such as lightning fixture or Sound
  equipment
• Curtains, back drapes
• Wind force.

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