A truss is used in architecture and structural engineering as a means of structural support. The most simple type of truss is a triangle truss. Simple triangle trusses consist of a series of triangles arranged so that the weight being supported is distributed evenly for maximum support.
A truss is made up of a framework consisting of many small triangles. The basic triangle in a truss consists of three beams connected in the corners by three joints. A triangle on its own could be considered a simple truss, but most trusses are comprised of many triangles, connected by a series of chords. An upper chord and lower chord will span the length of the truss, with at least two triangles along the chord. Brace chords will span the triangles vertically from the apex to the base. Once connected, the triangles within the chords combine with them to create several smaller triangles within, each dispersing and sharing in the weight, pressure and tension.
Trusses can be seen in many different building designs. Most commonly, they can be seen in bridge designs. Just about any wooden or steel bridge created in the last several hundred years employs some type of truss design. More intricate trusses are actually comprised with simple trusses working together for added strength. Home construction is made possible with trusses. Trusses can now be easily purchased assembled in a variety of sizes and strengths to more easily facilitate building homes.
The simple truss exists in several forms. The most basic and earliest known is the Kingpost, a triangle with a vertical tension rod connecting the apex to the base, thus creating two triangles. These can be used alone for short spans. Queenpost trusses further divide the triangle by placing a rectangle in the middle, thus creating three smaller triangles surrounding it. Howe trusses connect a series of overlapping equilateral triangles, each with a vertical tension rod. The triangles are connected by a chord at the top and base. They can be used to span large distances and hold much more weight than the Kingpost and Queenpost.
Simple trusses have been seen in building design in Europe since the 1500s. In the U.S., beginning in the late 1700s, trusses began being used in wooden bridge design, and by the 1800s, the U.S. was the world leader in wooden truss bridge designs. As wood was plentiful, truss building designs eventually found their way into other aspects of structural engineering. In the mid-1900s, trusses began being manufactured for homebuilding designs, and they're still the primary method of erecting most buildings.