Lattice truss bridge

A lattice bridge is a form of truss bridge that uses a large number of small and closely spaced diagonal elements that form a lattice. It was patented by architect Ithiel Town in 1820 and 1835 as Town's lattice truss.

Originally a design to allow a substantial bridge to be made from planks employing lower–skilled labor, rather than heavy timbers and more expensive carpenters, this type of bridge has also been constructed using a large number of relatively light iron or steel members. The individual elements are more easily handled by the construction workers, but the bridge also requires substantial support during construction. A simple lattice truss will transform the applied loads into a thrust, as the bridge will tend to change length under load. This is resisted by pinning the lattice members to the top and bottom chords, which are more substantial than the lattice members, but which may also be fabricated from relatively small elements rather than large beams.