Truss


     The definition of a truss is any of various
structural frames based on the geometric rigidity of the triangle and composed
of straight members subject only to longitudinal compression, tension, or both:
functions as a beam or cantilever to support bridges, roofs, etc. Trusses are
the most commonly used structural device used in architecture today. Trusses are
used in almost every thing they are in your attic, barns, buildings, and
bridges. A truss is used in architecture and engineering, it is a supporting
structure made of beams, girders, or rods usually made of steel or wood. A truss
usually takes the form of a triangle or combination of triangles, this design is
capable of carrying large amounts of weight. Trusses are used for large spans
and heavy loads, especially in bridges and roofs. Their open construction is
lighter than a beam structured platform but is just as strong. The parts of a
truss are the tie-beams, posts, rafters, and struts; the distance over which the
truss extends is called the span. A truss is formed by connecting the ends of
straight pieces of metal or wood to form a series of triangles lying in a single
plane. A truss is based on the fact that a triangle is a configuration that
cannot collapse or change its shape unless the length of one of the sides is
changed. The two most commonly used truss designs are the Howe and Warren
trusses. In 1806 the first patented bridge system, the Burr arch truss was used
in the US. The Town truss was invented in 1820, in 1840 the Howe truss was
invented, and in 1841 the bowstring was invented it was a breakthrough in
engineering design. The Pratt and Warren trusses were invented between 1838 and

1844. The first trusses were made of wood and used for building homes and roofs.

During the 18th and early 19th centuries cast and wrought iron were used, mostly
in the construction of railroad bridges. Later in the 19th century steel became
the most used truss material. Trusses are used also for the construction of
iron-frame industrial buildings and in roof and floor systems. They are also
used in the construction of certain industrial machines, such as cranes, lifts,
and in the design of aircraft and automobile frames. Two types of trusses are
the Howe and Warren trusses, Warren trusses are more efficient than Howe trusses
in carrying a load considering the weight of material used in the construction
of the truss. The optimum ratio of height to span length is anywhere between

0.23 and 0.41 for Howe trusses, and 0.16 and 0.39 for Warren trusses. The Pratt
and the Warren were simple skeletal forms that adapted well to iron and
eventually to steel that is why they are two of the most popular trusses used
today. Trusses are very important in today's world they help us cross huge
bodies of water, they hold the roof up over our heads, and they allow cranes to
be able to support huge amounts of weight when building giant skyscrapers. The
fact is the invention of the truss is just as important as the invention of the
wheel. Life would be very difficult without trusses.