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What is Truss Load?

A. Leverkuhn
A. Leverkuhn

Truss load is a figure for the amount of weight, and consequent pressure, on a truss. A truss is a type of structure, often made of one or more triangular pieces, that is commonly used in residential, as well as commercial, or public works construction design. A common form of truss is a normal roof truss that forms the load-bearing basis of the standard roof of a building.

Trusses are also used in larger setups such as bridges. In any use of a truss, the load is very much a part of truss analysis or truss engineering. Truss load has a direct effect on how a truss frame should be built.

Truss load engineers often rely on programs like AutoCAD.
Truss load engineers often rely on programs like AutoCAD.

In the complex truss analysis that is needed for most projects, truss engineers rely on new technology as well as traditional mathematics. Today, many truss designers may use autoCAD or similar software technologies to set up truss load simulations to determine what the theoretical load will be on a particular truss design. Engineers will be sure to factor this into the load bearing capacity of a truss structure to prevent the potential for structural failure in the field.

A common form of truss is a normal roof truss that forms the load-bearing basis of the standard roof of a building.
A common form of truss is a normal roof truss that forms the load-bearing basis of the standard roof of a building.

Engineers use several kinds of truss load to distinguish between different types of pressure on a truss. One common term is ‘dead load,’ which refers to constant load on a truss, such as part of the structure that will remain in place. Another kind of load is ‘live load’, which is types of load that will only be temporary. Live load includes things like snow and ice, which will only be a factor in truss load for a set period of time.

The Williamsburg Bridge, which crosses the East River in New York, uses a truss system.
The Williamsburg Bridge, which crosses the East River in New York, uses a truss system.

Engineers also look at the way that load will affect stress on a truss, and how forces will interact when load is placed on the truss. Truss designers may see load as an ‘event’ for a truss, and look at how stress changes. Another related term is deflection, which refers to the actual movement of the truss under a load. Though not normally visible to the eye, truss structures usually have a certain amount of flexibility by design, and will bend slightly as the truss load is increased.

Anyone involved in either residential, commercial, or public works construction knows that accurately accounting for truss load is critical for the success of a project. Project managers and other leaders in the field will often communicate with truss engineers several times over the course of a project to be sure any changes are being tracked according to how they will affect a truss structure. Seeing this aspect of construction through helps to avoid some major liabilities, and is part of a professional approach to building.

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    • Truss load engineers often rely on programs like AutoCAD.
      By: apops
      Truss load engineers often rely on programs like AutoCAD.
    • A common form of truss is a normal roof truss that forms the load-bearing basis of the standard roof of a building.
      By: Greg Pickens
      A common form of truss is a normal roof truss that forms the load-bearing basis of the standard roof of a building.
    • The Williamsburg Bridge, which crosses the East River in New York, uses a truss system.
      By: stockelements
      The Williamsburg Bridge, which crosses the East River in New York, uses a truss system.