Penetration through composite steel decking and concrete

[choneycutt]

During the renovation of a 20th story high-rise residential unit, it became necessary for a medium sized 28"X36" hole to be cut in the floor to perform a plumbing tie-in when the lower floor was inaccessible. The area of this floor will never be exposed to significant loads beyond a residential use.

The building is a 1980's vintage, 30 story steel building with concrete floors poured over traditional composite steel decking. The slab thickness varies from 7" to 5" depending on the area of the pan's corrugation.

I have found lots of guidance from Hilti as well as other resources that cover penetrations through this flooring type, but all assume the opening will remain permanent and the engineering measures to be taken assume this. In this case, the opening is to be closed once the access is no longer needed. Aside from placing a remnant of composite decking as a form, screwed to the overlap of the penetration, doweling and epoxying rebar on similar centers in to the concrete, placing like-kind mesh, and repouring the concrete, should any other reinforcing measures be taken?

Regards,
An appreciative new member.

 

[KootK]

My concern with what you've proposed is that:

1) I assume that the original deck was meant to be the tension reinforcement for the slab AND;

2) I don't feel that nominally screwing the deck remnant thing back in there restores that.

Any chance you could expand the opening to the nearest deck supports and then infill that with tension rebar where you need it?

Of course, treating the thing as a permanent opening, even with the opening, remains an option if that's the easier path.

 

[MasterTricks]

Would it not be possible to puddle weld the new decking on to the existing decking from underneath? Following the manu. specs for puddle welds.