Flare weld to Prestressed Girder Top Flange shear bars

[Ron247]

I see several generic details for welding a rebar to the shear dowels sticking out of the top of a prestressed concrete girder. Are the dowels A706 or will this require chemical analysis for the weld design?

I assume the weld is a flare since there are 2 curved surfaces.

Anyone have any insight to share? The 2 details below are from the Texas DOT. The lower detail is the welding one (option 2). Based on the shear note, I assume the weld needs to be good for at least 6 kips.

 

[dik]

I don't know, but they should be... just makes sense.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[STrctPono]

I'd put my money on the fact that A706 is probably not required for those "R" bars. AWS D1.4 openly addresses welding for ASTM A615 Grade 60 bar. What I question is how much that #5 tie bar is doing to stabilize the girder and how much capacity you can get out of the weld between the bars? Especially if it is welded a distance above the top flange. I've never seen anything like this before. In my neck of the wood we normally brace top and bottom flange with wood and then run a come-along strap around the outside of every pair of girders.

 

[gwynn]

If you can get the tie tight to the top flange, you can get reasonable capacity out of attaching to the stirrups. Not at the distance the conceptual drawing seems to show though. And I second your thoughts on weld capacity. My preferred detail is to cast sleeves into the web, just below the top flange chamfer, and run coil rods through. Partially because bridge designers here tend to not like contractors post installing anything into PC girders and partially because we often end up needing extra bracing capacity beyond what the designer specified during the deck pour. If we need the extra capacity, going through the web doesn't interfere with formwork or partial depth precast panels.