Steel truss and concrete column connection

[Jummybear]

Hi all,
I want to discuss such type of connection where steel truss is welded to anchor plate installed on the top of concrete column. Steel truss is welded with fillet weld. It is considered that joint is rigid when truss post is welded around. My question is it possible to consider such joint as pinned or semi-rigid when welds are provided only on 2 sides?

 

[Lomarandil]

I think Dik is thinking along the same lines I am. Here's a sketch include in the AISC manual section for "simple shear" connections -- intended for a beam connection, but rotated 90* could function in the same way for your column (to a certain level of ductility -- see the relevant parts of section 9 and section 10 for details)

Regarding the bearing surface -- grout is generally the preferred solution for simplicity and economics -- unless you need to allow horizontal translation (roller connection)

 

[Jummybear]

I'd prefer something that looks more like this, especially since wind load and stability demands on the column factor in. This is similar to how joist suppliers deal with these situations in the bearing seats of their trusses and you can trust that their solutions have been well vetted such that they represent sound practice. Even if you prefer to weld to an embed plate rather than anchor, I still like the proportions of something like this much better.

On your sketch there are 2+2 anchors, why not 1+1 on the centerline of truss support node?

Regarding the bearing surface -- grout is generally the preferred solution for simplicity and economics -- unless you need to allow horizontal translation (roller connection)

My assumption is to get rid of pouring work at column top and just provide neoprene pad or just some levelling plates (if needed). Have to be easier. On the other hand, grouting maybe a nicer solution,in this case levelling is porformed by bolt nuts.