RC Beam and Blockwork Lintel to Capping Beam Connection

[FreshMan2020]

Hi all,

Below is the connection one: RC beam sitting on top of capping beam. Does this connection look ok? If so, can I replace 'Z' bar with 'L' bar lapping in RC beam above only and drill into capping beam? Also, How do I determine the size and spacing of the 'Z' bar? All I can think of the use of 'Z' bars here is to resist the shear from capping beam due to soil being retaining, so I simply check the shear?. Anything else that I missed?

Below is the connection two: Blockwork lintel connecting to capping beam. What will you do? Is hilti rebars or the like an option? If so, can I use one row only considering I want the connection to be pinned as long as the shear passes.

Thank you.

 

[KootK]

- Detail (1) looks good to me.

- I don't love detail (2) and feel that it will create a weak shear transfer mechanism. Is there a block wall on top of the cmu lintel that you might run over top of the capping beam?

 

[KootK]

For the z-bars:

1) I'd be fine with drilled in L-bars but, if you're transferring load through shear friction here, it may be necessary to develop the bar on both sides of the joint.

2) I might consider that it would be nice to have the capping beam and slab acting compositely for flexure and size/space the dowels for that purpose as well as soil pressure. Maybe 15M @ 450 max no matter what the numbers say.

 

[KootK]

I've decided that I was too hard on detail (2). I still don't love it but I think it can work with the right attention to detail. And I'm not sure there's anything better without introducing a steel bracket etc that would be a corrosion vector.

How wide are the blocks?

How much load is being transferred?

If practical, I'd like to see a gaggle of stirrups at the end of the lintel capable of transferring the full shear load.

Depending on your load, you might also need hanger bars in your cap beam.

 

[FreshMan2020]

Thank you KootK. No, but there is concrete slab on top. So the design line load on the lintel is around 30kN/m. Lintel length is 3.7m, so the shear will be around 56kN. It is 190mm thick block with roughly 400mm height. What if I make this lintel to be non-load bearing so the capping beam is only to carry the selfweight of the lintel? Is this connection fine then? Any consideration for capping beam? (torsion shouldn't be a problem if I make it non-load bearing)

Yeah, there will be shear reinforcement in the lintel. I just didn't draw it for clarity as my main interest was for the connection.

How about the below connection (EA with anchors to shotcrete wall/piers) if I have to make the lintel load bearing? Is this better?

Thanks

 

[FreshMan2020]

The bar here, as I can think of, is to resist lateral load (shear) from soil. Generally speaking, if the bar is not use to resist tension, is cog/lap still required? Cog is normally used for bearing and prevent bar for pull-out, which is not the case when it is used for shear. Am I correct? With this kind of connection sometimes I see people use Z bar sometime I see people use L bar especially for PT slab (conventional slab too) and it confuses me.