Jointed knots
Introduction
A reticular or reticulated structure (also known as bar structure) is formed by a set of interconnected and crisscrossed bars joined together by means of articulated or rigid knots forming triangles.[1].
A lattice bridge is a special case of lattice structure, a type of truss bridge that uses many small, closely spaced diagonal elements that form a "Lattice (architecture)" lattice. The truss truss bridge was patented in 1820 by architect Ithiel Town.
Originally, it was a design that allowed the construction of a bridge of a certain span from relatively small planks, with the advantage that it avoided using large, very expensive pieces of wood, and required the use of less qualified labor for its construction. This type of bridge has also been designed using numerous relatively small and light iron or steel profiles. Small parts are more easily handled by construction workers, but the bridge also requires more additional support during construction. A simple truss truss transforms the applied loads into thrusts, since the bridge will tend to change length under the effect of the vertical loads. This effect is counteracted by attaching the truss members to the top and bottom chords of the structure, which are larger in section than the diagonal members of the truss, but which can also be made from relatively small members rather than using large beams.
When the structure is formed by articulated nodes, the bars will only work with axial force (traction or compression), while if the nodes are rigid the bars will work with axial force, shear and bending moment.
Belfast Truss
The Belfast Truss is a cross between the Town truss structure and a truss bridge. It was developed in Ireland as a shallow, long-span truss girder for industrial structures. McTear & Co of Belfast, Ireland, began manufacturing these wooden beams linked with metal fasteners around 1866. By 1899, spans of 24 m had been achieved, and by the 20th century, shipyards and aviation hangars were demanding increasingly longer spans.[2].
Iron or steel truss bridges
Howard Carroll built the first completely wrought-iron truss bridge in 1859, commissioned by the New York Central Railroad).
References
- [1] ↑ «Estructura reticular». Real Academia de Ingeniería. Consultado el 25 de junio de 2017.: http://diccionario.raing.es/es/lema/estructura-reticular
- [2] ↑ J. R. Gilfillan, S. G. Gilbert, The Historic Belfast Timber Truss - A Way to Promote Sustainable Roof Construction, 2002.: http://www.irbdirekt.de/daten/iconda/CIB9282.pdf
- [3] ↑ J. A. L. Waddell, Bridge Engineering Vol. 1, Wiley, New York, 1916; page 23.: https://books.google.com/books?id=nd4gAAAAMAAJ&lpg=RA1-PA23&pg=RA1-PA23