Non-Triangular (Rectangular) Steel Bracket

[Yousef ZAA]

Hello,
I have a precast connection connecting to different walls, I have a rectangular steel plate works as a bracket, I'm trying to design it, but I can't decide whether, I have to apply the triangular bracket design procedure or not, to my surprise I contacted AISC and they told me that most engineers, do consider the rectangular bracket as a triangular one and design for it.

I'm just curious to know what people do, at the end of the day I'm going to run a finite element model to feel it more.
Any help is appreciated.

 

[JAE]

I think the outer portion of the rectangular bracket just follows along and all the stress will follow the stiffness and "look" like a triangle once you run the FE analysis.