What is a metal truss?

We define a metal truss or steel truss a structural component that acts as a load-bearing element in a building. The truss is formed by an assembly of bars connected in nodes which are pinned. Meaning that they fail to resist bending moments or too big out of plan forces (planar truss). Bars and nodes form a rigid body that is not deformable in its plan. However, a truss can be a three-dimensional structural element that will be able to resist forces out of its plane as well (space frame truss).
In principle, the bars and nodes form triangles either in 2D or 3D which we know is the “strongest” geometrical form.

In a structure, a metal truss can have multiple functions depending on its position and geometry and can be:

  • floor truss – described as an element with parallel top and bottom chords. These elements will form the support for the floor layers above and the ceiling below. As static supports, we can consider the trusses simply or continuously supported. We calculate the height of the truss in relation to the distance between supports and by the local loads.
  • roof truss – described as an element that forms the shape of the roof. It can have various shapes (parallel truss, hip truss, truncated truss etc). The support conditions are similar to floor trusses.
  • column usually used in industrial buildings to form 3 dimensional vertical elements or in residential projects in order to locally stabilize a stud in a wall.
  • and space truss – in order to stabilize an element out of its plan we must use expand in the other direction as well.

To conclude, we exemplified the above-mentioned types of metal trusses in photos below.