Finding plugins or extensions

Is there a plugin or extension for find critical load or failure point of a wall, beam or truss

There are some roof and truss extensions:
http://extensions.sketchup.com/en/search/site/truss

Vali Architects of Hawaii has some professional architectural plugins:

But generally, SketchUp is a surface modeler, not a solid modeler. So objects are collections of vertices, edges and faces. They do not have built-in physical properties. (Mass, tensile strength, etc.)

Extensions would be needed to add this data as object attached attribute dictionaries.

There has been some success with adding physical extensions to the Ruby API, called Sketchy Physics. But it does not run on the newer 64-bit editions of SketchUp. (You’d need to install a 32-bit edition, which might limit your memory usage to ~3GB.)