Normal beam + inverted beam

[mats12]

There is mky question.
We have s concrete slab and 2 beams (marked in the picture below).
Im asking about the crossing (NODE) of two beams - one inverted and one normal? Is this common practice? Is it OK to do it like this?

What is important? any special detail/reinforcement?

 

[hokie66]

That can work, detailed correctly. But if I just read the plan, the wrong beam is shown with dashed lines.

 

[mats12]

hokie66 - tnx but i dont know what do you mean by wrong beam?

 

[hokie66]

Beam 1 is below the slab, thus should be shown dashed on plan. Beam 2 is an upstand beam, so should be shown solid. At least, that is the normal drafting convention.

 

[kc9508]

Just a guess, but I think what hokie66 means is that a dashed line typically indicates something below the slab. Per your sections, the beam that is dashed is the one projecting up above the slab.

 

[KootK]

What's important is successfully transferring the upstand beam reaction to the dropped beam without failing the slab locally in shear. If the end of the upstand beam terminates at the side of the dropped beam or over top of it, you're probably fine. If there's a gap, there could be trouble.

- how deep is the upstand beam from the top of the beam to underside of slab?
- how thick is the slab?
- how much overlap (or) gap is there between beams.

A joint detail 90 degrees to the one that you've shown would be helpful.

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.

 

[mats12]

@Kootk

There is no GAP, inverted beam end above (over a top) dropped beam. So dropped beam take reaction from inverted beam.


- how deep is the upstand beam from the top of the beam to underside of slab? 30 cm
- how thick is the slab? 16 cm
- how much overlap (or) gap is there between beams. NONE

 

[KootK]

In that case you should be just fine. Design and detail the upstand beam as simply supported. Extend your bottom steel to the far side of the supporting beam and terminate with hooks if necessary. Provide hanger stirrups at the joint as required. Design your upstand beam stirrups to transfer horizontal shear across the pour joint via shear friction.

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.

 

[mats12]

OK thanks!