Bonding (2) slabs in high wind zone
Bonding (2) slabs in high wind zone
(OP)
I have a project where there is an anticipated 170 psf suction force on a roof topping slab. The purpose of the slab is to protect the roofing below it. #3 ties were provided in a 6'x5' grid to anchor the slab to the precast double tee roof structure.
A series of unfortunate events for the contractor has resulted in a slab w/o the required reinforcing and the wrong fiber additive.
In lieu of tearing the slab off and starting over, the contractor has come up with the attached detail. They want to drill in new #3 "within an inch or two" of the existing #3. If the two slabs are adequately tied together, the resulting factored suction force is 118 psf or 3540# of hold-down force required per exist #3 tie.
I can't see how there will be adequate force transfer from the new #3 to the existing #3 to prevent the topping slab from becoming airborne during a 300 mph wind event.
Opinions anyone? (We can't drill new anchors into the dbl tees as we don't want to perf the vapor barrier that is below the insulation.)
A series of unfortunate events for the contractor has resulted in a slab w/o the required reinforcing and the wrong fiber additive.
In lieu of tearing the slab off and starting over, the contractor has come up with the attached detail. They want to drill in new #3 "within an inch or two" of the existing #3. If the two slabs are adequately tied together, the resulting factored suction force is 118 psf or 3540# of hold-down force required per exist #3 tie.
I can't see how there will be adequate force transfer from the new #3 to the existing #3 to prevent the topping slab from becoming airborne during a 300 mph wind event.
Opinions anyone? (We can't drill new anchors into the dbl tees as we don't want to perf the vapor barrier that is below the insulation.)






RE: Bonding (2) slabs in high wind zone
Depending on the type of bonding agent used, bonding agent itself can transfer 170 psf of uplift without any problem to the slab below. #3 bars on top of the bonding agent is just over kill. Try looking into SIKA ARMATEC-110 EPOCEM.
Prescribe, roughened interface and SIKA armatec and you should be good to go. Assuming that you have enough reinforcing to transfer the force to DT.
RE: Bonding (2) slabs in high wind zone
Doesn't look like you can get that here. The hooks would simply pull out of the concrete given enough load.
RE: Bonding (2) slabs in high wind zone
I wasn't concerned about the #3 tensile force being too high. I was concerned about the reality of the force transfer path from the new #3 to the existing #3.
RE: Bonding (2) slabs in high wind zone
RE: Bonding (2) slabs in high wind zone