Trapezoidal Beam Loads

OpenSees will never win any awards for documentation. Although many features, e.g., Concrete23, are not documented because no one uses them, a few useful items lack documentation.

For instance, did you know that you can apply trapezoidal member loads to beam elements?

You can do so with additional arguments to the eleLoad command with the beamUniform type.


The loads–force/length, transverse and axial–are input with respect to local element axes. The starting and stopping points, a/L and b/L, are normalized with respect to the element length, so the valid range for these points is 0 to 1.

Currently, this element load option only works with the 2D versions of elasticBeamColumn and forceBeamColumn. There’s an implementation for the 3D elasticBeamColumn, but I think it is triangular, not trapezoidal. No problem, just use two element loads–one uniform, one triangular–to get a trapezoid.

Esta pregunta se hizo durante OpenSees Cafecito.

7 thoughts on “Trapezoidal Beam Loads

  1. Thanks for that. I have a question on this topic. How can I assign a differential settlement on the supports? It is possible?

    Liked by 1 person

  2. How can I apply two distributed loads on the same element. For example a trapezoidal and a uniform. I have used the eleLoad command twice and am not getting consistent results.


    1. I found the mistake, it was in the plot of the results and not in the calculation. I take this opportunity to thank you for the work you do on your blog.

      Liked by 1 person

  3. “There’s an implementation for the 3D elasticBeamColumn”. Could you please give some hints on what is the commond/where to find it?


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