If I have a rectangular embedded beam in a slab supporting hollow core slab how is the connection and detailing between these two elements ? (any sketch would help)

If the beam parallel to the hollow core how is the connection between these two ? enter image description here

I need to know how the connection between the hollow core and the beam how is the bars between these two are connected ?

  • $\begingroup$ This might be my lack of engineering-English knowledge, but what's an embedded beam? Googling tells me it's a steel beam encased in concrete, but that doesn't seem to be what you're talking about. $\endgroup$
    – Wasabi
    Commented May 10, 2017 at 11:11
  • $\begingroup$ I meant by embedded as the whole section of the beam is in the slab (thickness of beam = thickness of slab), as not a drop beam. $\endgroup$
    – J.Daou
    Commented May 10, 2017 at 11:29

1 Answer 1


This depends on what connection behavior you would like to achieve. The hollow core slab manufacturer will typically have standard connection details or assist you with the connection design. Usually beams/columns are designed such that the prefabricated hollow core slabs can be lifted into place. Therefore, usually there are corbels or ledges for the slabs to sit on.

To get an idea, Hollow Core Concrete Pty Ltd (Australia) has Hollow Core Slab Technical Sheets on their website showing some typical connection details.

For example, I have taken the detail for an internal beam to hollow core connection from their website: internal beam to hollow core connection

It is worth discussing the design with the hollow core manufacturer to get an expert opinion. I always recommend using the experts instead of trying to re-invent something.

As @Wasabi pointed out I didn't address the situation you mention in the comments with the slab and beam having the same depth. This is a non-standard detail with regards to hollow core slabs. As I mentioned earlier, hollow core slabs are typically used in pre-cast construction. If you are casting integral beams, this removes much of the advantage of using hollow core slabs in the first place. You could just cast a voided slab in-situ for example.

If you need to use hollow core slabs in this situation there are potentially a few ways this could be achieved, for example: breaking out part of the hollow-core slab, adding the additional reinforcement then casting new concrete to fill the space; or using a concrete half-joint detail. The manufacturer may also be able to incorporate this beam into the design of the slab. Any of these non-standard connections would depend on your loading and other design and construction constraints and would likely need to be designed in collaboration with the hollow core slab manufacturer.

If you are willing to use steel-concrete composite construction you could use a typical slimfloor approach:


The space around the steel beam would be filled with concrete, and if you wanted to get very clever you could even add rebar in this space.

  • 1
    $\begingroup$ I think this is a good answer, but in the comments the OP states that the beam should have the same height as the slab, which your given design (which is just an example) doesn't allow. $\endgroup$
    – Wasabi
    Commented May 11, 2017 at 15:06
  • $\begingroup$ The answer is good but my main question was about a cast in place beam which is embedded in the slab I search the internet and I always get as the image you shared an inverted T-beam, but in my case as I said I need the connection between the hollow core and an embedded beam. $\endgroup$
    – J.Daou
    Commented May 11, 2017 at 15:55
  • $\begingroup$ @J.Daou, I have updated my answer. The reason you have not seen any details online is because this is a non-standard connection for precast hollow core slabs. You would likely need to design this in collaboration with the manufacturer. $\endgroup$
    – atom44
    Commented May 11, 2017 at 17:00
  • $\begingroup$ I know that this isn't a none standard connection that is why I have also designed the same slab as voided slab, I am just comparing which is the most economical for my project. thank you. $\endgroup$
    – J.Daou
    Commented May 11, 2017 at 17:42

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