# How to calculate the required thickness of a steel stiffener plate in a corbel/bracket

I am dealing with a setup similar to the image below. The horizontal plate is bolted to a horizontal concrete surface (Bridge Abutment). And a horizontal force is being applied to the the vertical. My question is how do you determine how thick the stiffener plate needs to be. I am looking to understand the general process and then I will turn around and try to apply my code (CHBDC).

My thoughts are you need to check to see if it will buckle. Treat it like a column and performa k*L/r check. k=2 for fixed fixed connection due to welds. not sure about section properties as they vary. Also not how to convert a horizontal point load in the middle of the plate into axial load? in the plate.

Was looking to stay out of FEA. Wondering if there was some basic first principles formula or something along those lines.

I am actually trying to size the green peices:

• FWIW: In shipbuilding we use the rule of thumb that gussets and anti-trip plates are never less than 0.75 of the web thickness. That always assumes that the aspect ratio is less than 3:1 or so. Your gussets may be longer than that. Dec 5, 2017 at 20:45