This is a diagram of the parts of a truss bridge.
<a href="//commons.wikimedia.org/w/index.php?title=User:PennySpender1983&amp;action=edit&amp;redlink=1" class="new" title="User:PennySpender1983 (page does not exist)">PennySpender1983</a>
self-made, <a rel="nofollow" class="external text" href="http://www.nps.gov/history/hdp/samples/HAER/truss%20poster.pdf">Trusses: A Study by the Historical American Engineering Record</a> by the <a href="//commons.wikimedia.org/w/index.php?title=Historical_American_Engineering_Record&amp;action=edit&amp;redlink=1" class="new" title="Historical American Engineering Record (page does not exist)">Historical American Engineering Record</a> was used as a reference. The HAER is part of the US governments and so the source is a public domain record.