lower clear cover on rebar 1

[structSU10]

I have a field condition where there is as little as 1/2" cover over bars that were specified to have 1-1/2" of cover. Beyond the environmental exposure is there any other issue with the bars functioning properly? There are no visible defects with the concrete placement on the face this may be an issue even though we had aggregates up to 3/4". Any thoughts?

 

[Lomarandil]

If flexural steel, maybe it would affect the strains used for moment capacity? (For very small reinforcing ratios)

 

[JedClampett]

The reinforcing will be prone to corrosion with that little cover. I'd make them coat the bottom slab with a migrating corrosion inhibitor as a corrective measure (or punishment, if you want).

 

[Aesur]

Another concern is fire ratings, there are minimum covers required for varying members, sizes, type of concrete and hour rating.

 

[KootK]

If this occurs over a meaningful length, at some point I would have to think that it would compromise your bond between bar and concrete. I'm not sure at what point that becomes a problem however, as slab cover routinely goes down to 0.75" successfully.

Are we beam or slab with this? If it's a beam, I'd also be curious about the state of affairs at any nearby stirrups.

 

[BridgeSmith]

There would be a severe reduction in the capacity of any laps where the cover is small, and the length required for development would be considerably longer.

 

[structSU10]

These are pilasters on a basement wall. they have about 2 ksi compression, some bending due to earth pressure.

Its a tempered space for parking so providing protection in some for is certain, I just don't know if its appropriate to go further than that.

 

[BAretired]

Its a tempered space for parking so providing protection in some for is certain, I just don't know if its appropriate to go further than that.

Please clarify that sentence.

 

[structSU10]

it will be kept around 50 F in the winter months and there are parking spaces they are located at the front of a parking space.

 

[BAretired]

Thanks.

 

[Aesur]

Are the pilasters on the soil side of the wall?

 

[EngDM]

If the pilasters are on the inside of the parking structure, and road salts are used, then the cover should be pretty large (60mm). At least where I am, the jurisdiction wants the design to account for salt water to splash onto the parkade walls.

 

[KootK]

These are pilasters on a basement wall. they have about 2 ksi compression, some bending due to earth pressure.

That statement takes me back to this one:

I'd also be curious about the state of affairs at any nearby stirrups.

If it's a pilaster, then you have ties.

If the pilaster bars need to work in compression, they're being restrained against buckling by the ties.

If the vertical bars have 1/2" cover, how much do the ties have?

Perhaps these are pilasters that do not need to utilize their vertical bars in compression.

Like EngDM, 1/2" seems a long way off for a parking environment.

 

[structSU10]

The ties have 1/2" cover, so the main bars have 1" cover. There was a construction error that led to this scenario.

 

[EngDM]

The ties have 1/2" cover, so the main bars have 1" cover. There was a construction error that led to this scenario.

What is the specified concrete type and cover on the structural drawings? IMO if it is a construction error and the face of concrete is exposed to the parkade, they should be fixing their mistake or you're just going to get corrosion.

 

[Enable]

Other than the environmental exposure, no, there are no issues. The main bars have more than the max thickness of the aggregate between them and the form, so they are fine.

As someone who has spent over a decade repairing parking garages, I can assure you that even if the bars were on the form it would probably be fine. I've seen all sorts of stuff that makes you wonder how things stand up, and on that scale 1/2" cover on ties (or stirrups) does not even register (I see it all the time in the old parkades).

 

[Just Some Nerd]

Another concern is fire ratings, there are minimum covers required for varying members, sizes, type of concrete and hour rating.

Not sure how it works in your jurisdiction/code OP, but if the min. axis distance/cover required for your fire rating isn't achieved, you're in for a bad time.

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Why yes, I do in fact have no idea what I'm talking about