Weird Steel Beam to Elevated Slab Detail 1

[cal91]

I'm working on an automated parking garage, and have got this connection to work by the numbers.

There is only a 3.5" overlap in elevation from bottom of 12" concrete slab to top of steel for this connection.

The reaction is 7.5 kips *1.6 = 12 kips (live load) in shear, no axial load.

I'm worried about the beam's torsional stability (despite there being 0 torsion even w/ unbalanced LL).

Any thoughts if this looks too funky, or something to add for stability without being too costly?

 

[JAE]

1. Can you extend the shear tab up through the horizontal steel plate? Grab more of the embed?

2. Can you change the three-bolt plate to be an embedded plate that extends up and over the top of the slab edge? Then use A706 rebar to tie in the embedded plate back to the slab better?

3. The three anchor bolts don't seem to carry much redundancy.

4. If there's salty water dripping off the cars then that little 3/16" fillet will go bye-bye.

5. Can you thicken the slab at that edge?

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[humanengr]

I can't tell what all the beam conditions are (compression flange restraint etc.), and what is the
function of the 1/4" steel plate.
Based on the available information restraint against twisting at load points and supports
is questionable. If you're using AISC specs. for design, those are basic requirements / assumptions for
Chapter F (probably AASHTO as well).
However, it appears web sidesway buckling should be checked.
It may help to connect the 1/4 steel plate (top flange cover plate)to the slab connection plate.
It may also help if you could further stabilize the beam by connecting the bottom flange to
the bottom of the concrete slab.

 

[JAE]

What about this?

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[KootK]

Is this new construction as opposed to existing concrete? Is the load significant or minor? If this is new construction and serious load, then I think that JAE nailed it with his sketch. If it's existing construction and minor load, you could do something like JAE's sketch but just post-fix bolt the angle(s) to the slab instead of using the embed plates. I think that your concern regarding the torsional capacity/stiffness of the joint is spot on. There doesn't have to be an explicit torsional load for there to be a significant torsional stability demand.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[BridgeEI]

JAE - is the rebar welded to the angle more preferable than using studs? I live in a world where welding to rebar is a no-no. I assume it helps clean up the Appendix D calls also. I'm a bridge person who likes looking at vertical details so I try to educate myself.

 

[JAE]

You would use ASTM A706 material instead of A615. A706 is weldable. You could also use deformed bar anchors - I can't recall their ASTM name.


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[spats]

Deformed bars are ASTM A 496, low carbon.

 

[JAE]

Thank you, spats.


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[cal91]

Thanks to all. Doing something very similar to JAE's sketch. Much appreciated, JAE.