epicore/metal deck connection to upset concrete beam

[struct_eeyore]

I'm wondering if anyone has encountered a condition as detailed in the attached image. I have a epicor (dovetail) deck that comes in to the face of a concrete beam - this will obviously need to be a monolithic pour. Other than designing the connection for shear and moment along the length of the pour, are there any additional, extenuating circumstances here? I'm thinking if connection between the epicore slab and the concrete beam is rigid, then there are no additional torsional considerations - or no? Any input greatly appreciated.


[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1706672185/tips/connection_bftvmi.pdf[/url]

 

[BAretired]

I have not used Epicore deck, but it seems clear that the deck would normally be supported on a steel beam, joist, steel angle or concrete corbel; some type of flat surface with provision for attaching it.

Your section shows no support under the deck; it just butts up to a concrete beam. Perhaps a continuous angle or concrete corbel could be provided on the beam to support the deck, but it is a rather unusual detail.

I have a epicor (dovetail) deck that comes in to the face of a concrete beam - this will obviously need to be a monolithic pour.

That is not obvious to me. In fact, it would seem more likely that the beam and corbel would be poured first, then deck and slab placed, not unlike hollow core slabs.

 

[dik]

...little plates cast into the face of the beam secured with headed studs. A ledger angle, maybe L3x3x1/4 welded to this to support the deck on... I just noticed, but for composite floor deck the ribs are narrow and are spaced apart to save concrete. This appears to be the other.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[bones206]

I’ve seen longspan deck companies that have details for monolithic “slab-beams”. Might be something to look into, then adapt the construction and design methodologies to this upset beam condition.

 

[zackngineer]

I have not used Epicore deck, but it seems clear that the deck would normally be supported on a steel beam, joist, steel angle or concrete corbel

The Epicore deck does not need additional support unless there is an extraneous circumstance. That's part of its selling feature is that its super easy to install. Just put the lip of the panel on the edge of the wall and call it a day. I attached their standard detail for these connections. The detail doesn't show the perimeter slab bars but I've never seen it without them. We did have a situation on a job recently where they had to do a cold joint at a balcony pour. In that instance, we would have had to specify something like a steel angle for bearing. The Epicore engineer took responsibility for it so I'm not sure what they decided to do there.

Regardless, I don't know the answer to OP's question. I have never personally checked for torsion at this connection but I can imagine there would be circumstances where that may come into play. Usually, our torsion values in standard residential/commercial designs are so low they are not relevant.

OP, the Epicore panel needs to be shown protruding into the concrete beam, see attached detail.

 

[bones206]

The end of the decking should be supported by shoring during construction, and the slab-to-beam connection designed/detailed per typical ACI-318 one way slab requirements.

 

[zackngineer]

Usually they just use a wood ledger to the masonry if there's a wall below but for this instance yeah it'll require shoring posts.

 

[BAretired]

With an upturned beam and not too much concrete below the deck, the left hand detail is unacceptable. A properly reinforced corbel is a better detail. There is some torsion to consider, but it is not likely to be a problem.

 

[zackngineer]

Maybe that's a "better detail" but I don't know how you can say its not acceptable if it's designed for it. They do it with slab beams.

 

[dik]

Something like the attached... likely the least costly... needs welder trade on site, but a lot cheaper for formwork and reinforcing and a lot faster?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[zackngineer]

I guess where I'm having a hard time understanding why we're talking about alternate details is because Epicore was specifically designed to eliminate these alternate bearing conditions. That was how it was explained to me a few years ago by the prez of a shell company we deal with. He was selling it as an alternative to hollowcore because hollowcore has to be installed after the walls are poured. The benefit to Epicore is that its all one pour. Walls and floor get poured together then you build the next level of walls and floor on top of it and so on.

I've included a few pictures to show you what I mean. The epicore and tie beam are poured together. There is no bearing angle, no corbel.

 

[BAretired]

Maybe that's a "better detail" but I don't know how you can say its not acceptable if it's designed for it. They do it with slab beams.

I do not believe that a 35mm unreinforced projection of unknown depth is a reliable support for an unknown reaction. For a downturned beam or a wall, it may be okay, but we are talking about an upturned beam without specifying the height of concrete below the deck. Concrete has been known to break off. Furthermore, it is impossible to inspect after pouring.

It might look good, but it is not a good detail in my opinion.

This is really scary!