Wall load on Hollowcore with column cut out

[precast123]

Hi everyone.

I have a hollow core, loaded with block wall(please see attachment). 300mm column cutout is there and wall load is present on this unsupported part. I want to ask, what would be the possible failures in the hollow core slab. Shear failure because of reduced bearing, failure in core along the span or torsion in hollow core, etc. Note that no screed is present to distribute the load. Will the grout (shear key) can distribute this load to other hollow core? Do I really need a steel corbel or support in that 300 cutout part?

Thanks!

 

[121974don]

Hi ,

provide sufficient information aside from "SECTIONAL VIEW" only..like Plan drawing so we could determine the exact location of the wall and so forth.

 

[precast123]

Plan

 

[KootK]

I'd say that through core shear and flexure, I'm the transverse direction, would be your primary issues (similar to torsion). I expect that both would be fine, however. I doubt that a shear key connection would get you much help from the neighbouring planks. If it were me, I'd add some bearing angles to the columns similar to what one would do with metal deck.

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.

 

[precast123]

@ KootK ..Thanks for reply . I have provided steel corbel to avoid complications. Now I am struggling to prove by code and calculation that the hollow core is not safe without steel support at the cutout.

 

[precast123]

Other engineers are on the opinion that the grout between the hollow core will transfer the load to the adjacent planks as per the code.

 

[KootK]

other engineers are on the opinion that the grout between the hollow core will transfer the load to the adjacent planks as per the code.

What code provision would that be? I've only seen load distribution recommendations in the PCI manuals and manufacturer's literature. And, in all cases, that is simply the distribution of load to determine shear and bending about an axis transverse to the planks. The load distribution usually looks like a trapezoid at the edges of the deck.

That trapezoidal load distribution does little to help with your situation here unfortunately. Your exterior plank cantilevers 300 mm beyond it's supports and that results in shears and moments about the longitudinal, unreinforced axis of the edge plank.

The cantilever moments and shears would exist even if your floor deck was cast in place concrete. The only difference would be much higher shear capacity and, hopefully, the presence of top bars perpendicular to the edge.

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.

 

[121974don]

Thus, steel corbel is good but introducing an I-Beam is much better (to avoid failure in core ) will do.Most likely if you install CMU as your wall then you should install support in it both lateral side and longitudinal side.