Mechanical opening needed after fabrication/erection 1

[EngineerEIT]

I have a situation where MEP needs a chase adjacent to a girder after the steel has been fabricated and erected. The floor system is composite metal deck on WF beams / girders. MEP needs 3 ft clear opening and the beams are spaced 9 ft apart. I've checked the girder considering concrete effective flange only on one side and the beams with no studs for the first 3ft and everything checks out OK. My recommendation is to put a pour stop on both sides of the opening and wait for the concrete deck to reach 75% of its strength before cutting the hole in the deck. Is there anything else I should recommend? I was thinking to add some reinforcement to the slab, 1 bar in bottom of a couple adjacent flutes to the opening and hooked reinf perpendicular to the deck near the top of the slab.

The slab has fibers instead of a wire mesh.

Here is a quick sketch:

 

[haynewp]

I would add in rebar at the re-entrant corners and extra transverse and long. bars in that small segment at the very end that continue over into the right hand bay. You should have bars over all girders on the project anyway. I would put hooked bars on the right side of the girder with the hooks along the edge of the openings assuming this is an interior bay.

 

[haynewp]

Actually I would consider eliminating that little end piece all together and have a continuous pour stop on the left side of the girder aligning with the left side of the openings.

 

[EngineerEIT]

Thanks haynewp, I knew there was something I wasn't thinking of