Core Filling on SOMD

[Boiler106]

Does anyone have a method for infilling cored holes in slab on metal deck that can be done from above without having to secure the infill from below? Holes range from 4" to 9" in diameter

We have been asked to use this system in the pic below but i need a way to secure the concrete in the hole after its placed. We have come up with a few options:
[ol 1]
[li]drilling #3 bars diagonally into the hole from the adjacent slab surface and field bending it horizontally.[/li]
[li]drilling tapcon screws into the sides of the hole. we dont like this since they would only really be engaging the grout in the upper portion of the infill.[/li]
[li]Reaming a cone shaped hole to keep the plug from slipping out. This seems difficult and could lead to a damaged slab in the vicinity of the opening.[/li]
[li]Relying on friction of the grout and the existing concrete. Not a big fan.[/li]
[/ol]

 

[RangeRock]

Would think your best bet is to dowel some bent #3 bars into the core as you mentioned. Providing a hook in the dowel will help "grab" the infilled core. and keep in place. Thinking you'd want to get at least (4) per hole e.s. radially.

Out of curiosity... what's the hold-up w/ using PAF's to temporarily create a form on the bottom side of the slab and then removing after the conc. has cured?

 

[Retrograde]

This is what I have done in the past:

 

[MotorCity]

Not sure if the floor finish is a concern, but I've recessed a plate into the top of the slab and attached with countersunk concrete screws. Works great.

 

[Boiler106]

@rangerock - there are about 4 layers of conduits plus another two layers of pipes running throughout this process facility. some of the cores can be done from below but finding a solution from above would make my design-build client happy.

@retrograde - thats a nice solution but it looks like you would have to have someone below the slab to install that plywood backing

@motorcity - i like that idea but i think firesafing might be an issue