How to create Line load

[Parham.13.20]

Hello all.
I have modeled and partitioned an I-beam in Abaqus. I want to apply a triangular line load along the centerline of the I-beam's web (red Line in picture). However, when I try to select the centerline, it's not selectable. How can I accomplish this?
Please note that I do not want to create the I-beam using the 'Wire' sketching tool and then assign an I-shaped section to it.

 

[FEA way]

Line load can be used only for beam elements. In this case, you can either apply a pressure load to the whole top face (with an analytical expression field to define its variation along the length of the beam) which would be a standard approach or e.g. create a node set for that edge and apply a concentrated force load with an analytical expression field to it. Still, I wouldn't apply it to this edge only.