Upside Down Drop Panel - Retrofit?
Upside Down Drop Panel - Retrofit?
(OP)
I have a 6" roof slab, flat plate from the 70's. Due to a new slab opening and some increases in loading I have a column that does not meet punching shear requirements. There is no access to reinforce from below but I have complete access from above.
I have seen that Hilti has a post installed shear reinforcing system but they do not sell it in the US.
Has anyone done or seen a post installed upside down drop panel? We would roughen the existing slab. Then install some type of reinforcing, possibly drilled and epoxied diagonal bars... not sure of this detail yet. We would then pour a rectangular "drop" on top of the slab.
I have several concerns about doing this but my main one is developing rebar from the new upper panel into the existing slab.
Any thoughts on this?
I have seen that Hilti has a post installed shear reinforcing system but they do not sell it in the US.
Has anyone done or seen a post installed upside down drop panel? We would roughen the existing slab. Then install some type of reinforcing, possibly drilled and epoxied diagonal bars... not sure of this detail yet. We would then pour a rectangular "drop" on top of the slab.
I have several concerns about doing this but my main one is developing rebar from the new upper panel into the existing slab.
Any thoughts on this?






RE: Upside Down Drop Panel - Retrofit?
If the hole is the only reason for the problem, why not reinforce the face of the hole with channel or other?
RE: Upside Down Drop Panel - Retrofit?
Back to the first question - what about developing the bars in the upper "drop" into the original lower slab?
RE: Upside Down Drop Panel - Retrofit?
RE: Upside Down Drop Panel - Retrofit?
thread507-307810: Upside down Drop cap
This was for new construction, so the upstand to be cast monolithically. Developing the horizontal shear in a relatively small area between the new and old is problematic.
RE: Upside Down Drop Panel - Retrofit?
RE: Upside Down Drop Panel - Retrofit?
RE: Upside Down Drop Panel - Retrofit?
Slabs don't have to be "concrete bonded" to exhibit composite action...the doweling will do that....but then, composite action in this case, though not really required, won't hurt either.
RE: Upside Down Drop Panel - Retrofit?
BA