It’s easy to confuse surface loads for area loads; just remember Area Loads apply to members, and Surface Loads apply to Plates.

Area Loads are only for MEMBER loading. Area loads are applied to polygons with three or four sides and the tributary area of that polygon is applied to the members below it. Below you can see the distribution of loads to the members.

 Surface loads can be applied to plates. Surface loads are converted to equivalent corner joint loads based on the plate area tributary to each corner joint.

Wall Surface load can be applied tapered and can start and stop anywhere on the wall.

If you’re applying a Area Load to the a model with both Plates and Members, only the Members will be loaded.

Tags: Loads, RISA-3D