Grossly premature foundation loading

[SubcontractorPolice]

So these subcontractors pour a 24" wide by 10" deep shallow foundation with 3,000 psi concrete covering only horizontal steel. This is the perimeter foundation for a future stem wall. 30 minutes later they stab in the vertical steel into wet concrete and make feeble attempt to hook under the covered horizontal steel.

Then these jokers come back not 15 hours later and construct a CMU masonry block stem wall four blocks high over half the foundation and call it quits. They'll come back to finish the perimeter stem wall foundation tomorrow.

So at best you'll have 15 hours of cure over half the concrete and 30 hours over the other half. The concrete is not high early strength. No cylinders pulled, nothing. They'll probably bring fill the next day and bring it level with top block minus 4" then pour the slab the next day.

What is going to happen to the concrete that's been completely loaded, stem wall, slab and all not even 5 days from first pour? You have to be completely incompetent to allow this kind of practice.

Ranting in Savannah Georgia.......

 

[RHTPE]

Wet-setting the dowels (or verticals) is not uncommon for residential or light commercial structures. While not the best practice, if the concrete has not yet attained its initial set what is the real problem, aside from being poor practice?

The 10" x 24" strip footing at 15 hours has no doubt achieved some strength. Depending on the concrete producer's history, it could be up to 1,000 fc'. What is the actual load applied to this footing from 4 courses of CMU compared to the total design load for the footing? I suspect it is but a small percentage.

Aside from poor practice, I'm not convinced there is a serious problem here.


Ralph
Structures Consulting
Northeast USA

 

[Ron]

I agree with RHTPE....poor practice, but not likely to cause issue.

 

[CELinOttawa]

If this is in a seismic area, the hook bars will not have the design strength required. I have an old report showing something like up to a 60% loss of pull out strength. Be damned if I can think of where it is... Effectively that is the worst possible, however; ie: If you were to wait until the concrete was near-set, and then force the hooks down and in.

Non-seismic area, likely barely acceptable. I would be asking for an extended warranty and perhaps a bond in the Owner's favour. Otherwise it is a clear violation of basic (not even best as a test) practice, and would be sufficient cause to force the Contractor to remove and replace. But what a fight!

Read them the riot act, make it clear that any further violation of best practice will not be tolerated, get it minuted, and move on. Very unlikely to be worth your time and the owner's money, albeit this should set off your warning bells for how much monitoring now needs to increase.

IN EVERY CASE where a contractor engaged in this kind of corner-cutting BS, I later found horrible site issues. By horrible I mean entirely missing bars, the wrong size of welded wire mesh, anchors meant to be epoxied to 200mm which you could pull out with your hand (10mm or so epozy), etc, etc, etc.