A truss is any structure that relies on a triangular design for strength and stability. It may be as simple as a three-sided triangle used in a bicycle frame to a multi-dimensional structure at the base of a tower or bridge. Different truss types can be categorized by their design, function, or material makeup. For example, pre-fabricated wooden trusses are used in home construction, while units made from steel or other metals are used to build bridges and commercial buildings.
One of the easiest ways to distinguish different truss types is to determine whether they exist in a single plane or multiple planes. A planar trust is flat, and exists in a single plane. One example of this could be a single triangular structure used to frame the face of a roof. Another major truss type is the space frame profile, which features a three-dimensional design that exists in multiple planes. A common example of this is the metal pylon towers used to support high voltage wiring.
Perhaps the most common truss types are those used in residential construction. These units are traditionally made from wood, and are a pre-fabricated alternative to standard stick framing. A floor truss consists of two parallel beams joined by a series of triangles that help to distribute the load placed on the beams more effectively. Roof truss systems are typically triangular in shape, and may be planar or space frame in design, depending on the shape of the roof.
Other truss types include those constructed from various types of metal. Steel truss systems may be used to form the walls, floors, and ceilings in a commercial or industrial building. Specially-constructed steel trusses can also be used to form complex architectural elements on the interior or exterior of a building. Aluminum and other lightweight metals are even used to form modular or portable trusses. Truss types of this kind include lighting truss units or portable models designed for displays or staging.
Many people associate trusses with bridge design. In bridge construction, trusses can be made from wood, iron, steel, or a variety of composite materials. The earliest bridge truss types consisted of a simple kingpost, with a single triangular support reinforced with an interior vertical post. Over time, beam-style bridge trusses that resemble a standard floor truss system have allowed bridges to span greater distances. Advanced models like the cantilever or camelback truss have further increased the span and safety of truss bridges.