Types of Steel Trusses

Steel trusses are used to provide extra stability to floors and roofs. Steel is often used in combination with wood, and these hybrid systems are popular for multi-story buildings, as they provide a great deal of strength and stability to the floor and roof that they support. Steel trusses can provide a great deal of structural integrity. There are also many different types of steel truss systems commonly found. These different systems provide their own sets of advantages, and while one system will be appropriate for a specific application, it may not be for another. Different systems are used to work with and around different architectural obstacles.

Parallel Trusses

One of the most often used truss systems to support floors is the standard parallel truss system. In this system, there are two beams which hold the supports. Parallel trusses are used for either steel, wood or hybrid systems.

Pratt Trusses

One of the older and most popular truss systems, this consists of two parallel chords of either wood or steel combined with diagonal beams between them providing extra support. Pratt trusses use more materials and are, therefore, more expensive and difficult to build, but they also provide a great deal of extra support.

Pitched Trusses

Pitched trusses are amongst the most common types. These systems use angled supports placed inside a triangular frame. These designs provide adequate support and stability in many situations, and they are also quite versatile. They can be found with many variations in spacing, size and shape.

Queen’s Post Trusses

These systems use two vertical supporting beams, which are then connected together using a horizontal beam. Further beams are installed at angles on each side of the vertical beams. These are only used for supporting smaller roofs and floors and are a popular alternative to the king’s post trusses.

King’s Post Trusses

Amongst the least advanced type of truss systems, the king’s post truss system is easy to build and cost effective. Two angled beams are used in this design with a vertical beam across the center for additional support. Because of their simplicity, this system is only suitable for very small structures.

Vierendeel Trusses

Vierendeel steel trusses are used in many applications, especially in certain commercial buildings and other large structures. In this design, vertical beams are used with open rectangular spaces between them. This type of design is extremely resistant to pressure and bending, hence the reason why it is widely used in bridges of any size.

Lenticular Trusses

Another design popularly used in bridges is the lenticular steel truss, in which the bottom and top chords are curved to form the shape of a lens. Between the bottom and top chords, vertical supports are used, which usually also have angled bars connecting two of the corners.


A K-truss is a steel truss design which is also popularly used in bridges. As the name suggests, the supports in this system are shaped like rows of the letter "K".