Truss
A truss is a structural framework commonly used in engineering and architecture, composed of long, rigid members connected at their ends to form triangular or more complex shapes. This design allows trusses to efficiently bear loads under tension and compression, making them essential in applications like roofing and bridge construction. Traditionally, early roof structures were built using individual wooden boards, but innovations have led to modern truss designs that utilize metal plates to connect lumber, significantly enhancing construction efficiency and uniformity.
Trusses can be crafted from wood or metal, and their strength enables them to span larger distances than traditional stick-built structures. Various types of trusses exist, including the Pratt, Warren, North light, saw-tooth, and Fink trusses, each adapted to specific engineering needs and aesthetic preferences. The use of trusses has revolutionized building practices, allowing for quicker installation while providing robust support against environmental stresses, such as heavy snow or rain. As a result, trusses remain a pivotal component in contemporary structural design and construction.
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Truss
In engineering and architecture, a truss is a structural form made of long, rigid pieces (known as members) attached at the ends in triangular or more complex patterns. The strength of trusses under tension and compression forces makes them valuable in many structural engineering applications. They are commonly used as a framework for roofs and sometimes floors in buildings, as well as in the support structure of bridges.
Trusses in Roof Construction
The earliest wood-framed homes were constructed with the equivalent of stick-built roof frameworks made of logs. A stick-built roof support is made of individual boards cut to size and nailed together to form the desired shape of the roof. Eventually, people figured out how to make roof structures by attaching the logs and sawed lumber into a triangular shape supported at the joints with flat panels of wood. These would be hauled into place to form the roof.
In 1952, A. Carroll Sanford, a Florida-based inventor, created and patented the first modern truss using metal plates shaped and sized to perfectly hold two-by-four lumber together. His company, Sanford Industries, began manufacturing trusses in a variety of shapes and sizes. This technique revolutionized the building construction industry by allowing quick, easy, and uniform construction of trusses for all sorts of projects.
Trusses, sometimes known as open web girders, are formed by making a series of triangles of different sizes and shapes and connecting them together. An engineer determines what shapes and sizes the triangles should be to provide the best possible support for the load they will carry, allowing for the weight of the roofing material as well as any rain, snow, ice, etc. The forms can be made of wood or metal and are reinforced at the connection points with steel plates created in the optimal shape to support each jointure.
There are several different general types of trusses. The Pratt truss looks like a series of capital letter N's encased in a long thin rectangle. The Warren truss is a rectangular framework filled with sets of right angle isosceles triangles placed with their long sides together. A North light truss is shaped like a scalene, or unequal-sided, triangle with other unequal triangles inside as support. A saw-tooth truss is several North light trusses placed next to each other like the teeth in a saw for multi-peaked roofs. The most common house truss, a Fink truss, has an equilateral triangle in the center and matching pairs of triangles down each side to complete the support.
Trusses are often used because they are faster to install, since the construction is done away from the building site. Their design means they can span a greater distance than a stick-framed structure. They are also generally stronger and provide better support than most stick-built forms.
Bibliography
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