Troop 8 Truss Presentation

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29 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

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Troop 8 Truss Presentation

What are Trusses?


A truss is a type of framework, usually comprising straight struts and
ties, which is designed to be stiff.


This is achieved by the inclusion of a sufficient number of triangles.


Some or all of the joints may be fixed rather than pinned, but the
main contribution to the stiffness is provided by the triangulation.


Before steel became an economically useful material, trusses were
made of wood or iron.

Examples of Trusses?

Why Triangles?


A triangle is the only rigid shape that can be made with
pinned joints
-

so there is only one set of angles that will
go with a given set of sides.


Stable With Applied Force

Unstable with Applied Force

Plank Bridge?


Bridges experience two forces


compression (push
together) and tension (pull apart). All materials have
compression strengths and tensile strengths.


Consider the beam bridge with a load


i.e. your weight.


The weight causes the beam to bend. There is a
compression force on the top and a tension force on the
bottom.








A truss adds rigidity to the beam, therefore, increasing
it’s ability to dissipate the compression and tension
forces

Bridge Shapes?

Bridge Shapes?

(Continued)