A structure that includes a number of bars pin attached at their ends to develop a solid framework is a truss. Loads and reactions are implemented to the truss only at the joints. Triangular elements containing the bars on the upper chord is how the truss is usually formed and under compression and along the lower chord under tension.  The trusses are mostly utilized for bridges, long span roofs, electric tower, and space structures. More about this in the link bellow.

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