3D Weld Section Modulus

[ericant]

Hi

I am placing a plate above an existing beam to beam connection. Attached is a picture of the configuration in plan view. The red dot shows the location of a concentrated load and OOP moment. In designing the connection of the bent plates (drawn in blue) I am wondering how to go about finding the section modulus of the combined welds given a 3-sided weld at each end of the bent plate. With this I would like to use the elastic method to determine an appropriate weld thickness. I am having difficulty with the fact that the welds are on separate planes.

https://imgur.com/a/lmYsISs

 

[3DDave]

There's no attachment; it's a two step process. 1) Upload the picture. 2) Copy the URL from the upload and paste into the comment/question.

 

[phamENG]

I'm not entirely sure I understand your sketch, but here's my thought:

Simplify the problem. Don't attempt to look at all of the welds acting together. Model the joint with the plates as members with end constraints as you want the weld to behave (fixed, pinned, etc.).

Once you've done that, figure out the reactions at the end of the plates. Now you have 4 (or more likely 2 sets of 2 identical) end reactions with planar welds. Then employ either the elastic method from AISC or the slightly more convenient elastic method presented by Blodgett.