concrete slab on ground joints 4

[rowingengineer]

I am told that the sawn joint detail with the reinforcement continuous is out of date (first detail in the PFD). Apparently the second detail should be adopted as the standard.

I am told everyone does the second detail in the PDF these days. However I have been using the first detail for years and never had any more problems with it then I do with the second detail. I have also worked at four practices that have used the first detail as standard.

So what I would like to know is what your standard sawn joint or tool joint detail. Do you still use number one or are you using number two and WHY?


Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that they like it

 

[dik]

I generally use 2" cover top and sawcut 1-1/2" deep... depending on the slab thickness... For an 8" slab, if a single layer of rebar, then 2-1/2" cover and 2" sawcut...

Dik

 

[RHTPE]

As with all concrete construction, the entire picture must be considered. The particular mix and its behavior needs to be understood; the proper time for finishing; the ideal strength for saw-cutting; the slab thickness & reinforcing; the weather/climate conditions at the time of placing & finishing; etc.

To arbitrarily say that slabs "shall be saw-cut within 24 hours of placing concrete" may not be the correct instruction to the contractor for the job-specific conditions. Saw-cutting at 23 hours after placing could have a vastly effect than saw-cutting 1 hour after placing. Yet both meet the requirements of the detail.


Ralph
Structures Consulting
Northeast USA

 

[dik]

Ralph... I generally note that about six hours or eight hours after finishing (as soon as the slab can be cut without ravelling of aggregate) and using some of the Sofcut saws this can be reduced to an hour or two...

Dik

 

[RHTPE]

dik:

Ralph... ever consider that the sawcut location was off by a foot or so? <G>

Dik

Not this particular joint - it was properly centered on the columns. The shrinkage crack was a foot or so away for most of its length.


Ralph
Structures Consulting
Northeast USA