Moment transfer through weld.

[Althalus]

I'm thinking that the project specifcations team has not looked at the load path carefully enough. But maybe I'm missing something.

[ol 1]
[li]I have an embed plate that has an array of nelson studs welded to it.[/li]
[li]The studs are embedded on the underside of a concrete structure.[/li]
[li]On the underside of the embed plate is an HSS being used as a hanger for a large trolley. It is welded to the embed plate via fillet weld all around.[/li]
[/ol]

Now the loading:

[ol 1]
[li]When the trolley is loaded at one of the hangers, there is a lot of load on the embed plate through the HSS.[/li]
[li]That weight pulls down on the embed plate at locations between Nelson studs. I'm thinking that this is a problem.[/li]
[li]The project procedures dictate that we only check for shear and tension on the studs. The logic being that since the studs are 100% embedded in concrete, there is no moment. They can't bend.[/li]
[li]That may be so. But when the HSS is pulling at a location between studs, then the plate acts as a beam which is rigidly supported by the studs.[/li]
[li]Unless there is some justification that says the plate simply won't tear away from the studs, I believe it will tear away from the studs.[/li]
[/ol]

[ol 1]
[li]The studs are 5/8" diameter.[/li]
[li]The plate is 1.25" thick.[/li]
[li]When modeling the studs as a fixed support for the plate, I get a large moment at the studs/supports.[/li]
[li]That's fine for the plate. But it is too big if the resisting area (the weld between the plate and the anchor) is based on the 5/8" (circle) stud.[/li]
[/ol]

 

[dauwerda]

Your plate should be thick enough that assuming it as rigid is a safe assumption i.e. it won't rotate enough to cause any issues. 1-1/4" sounds like it may be depending on the actual loads and dimensions.

I would also suggest either making a post in the structural engineering general discussion forum with a link to this post or deleting this post and reposting in the structural engineering general discussion forum in order to get more views and responses.