Masonry Reinforcing Placement 2

[SperlingPE]

I need some information.
Is there documentation that would allow a mason to place fertical reinforcing after the cells are grouted and after the grout has begun to set up (10-30 minutes after the cell is filled)?

My understanding is that reinforcing is in place prior to laying up the units or can be placed after the units are laid up (with the use of positioners). If reinforcing is placed after the units are laid up, grouting is never done before the reinforcing is placed.

 

[concretemasonry]

Where is the construction and what is the local code jurisdiction/standard? - U.S., Brazil, ????

How high are the walls and is it a flexural wall or a reasonably axially loaded wall?

Normally, reinforcement must be in place before grouting. The placement tolerence/positioners can vary widely. Clean-outs and inspection practices also vary widely depending on demonstrated performance (video, etc.).

Dick

 

[SperlingPE]

14' high walls
low lift grout method
according to my CA, bars are being pushed (hammerred at times) into the grout
IBC 2000 - middle of the USA
exterior load bearing walls - typical floor and roof load for a two story building
wall supports vertical load and lateral load.

 

[csd72]

If the grout is in place, how do you verify the position of the reinfocement? At the bottom it could be up against the inside of the face shell and on the opposite side required for tension!

If the reinforcement is in there for strength, then I would not take responsibility for it. I never put myself in a position where I am taking responsibility for something I could not observe on site.

 

[TDAA]

If the grout has set enough to where the bars have to be hammered into place, then what sort of bond do you think you are getting between the grout and bars?

 

[scottiesei]

Yeah, that's crazy, I've never heard of that either. Just have them go back and knock out some face shells adjacent to the current filled cells and dowel some new rebar into the tie beam and footing.

 

[swivel63]

so it's nothing like wet sticking a bar? the actual grout is already hard? but yea, you'd have no idea where that bar is in relation to the dowel coming up.

 

[SperlingPE]

I am in agreement with the comments above and I have an idea for fixing it.

My question was where is the documentation that would allow the above practice or disallow it?

 

[concretemasonry]

Definitelt substandard construction practices that should not have been permitted.

Any time you have low lift grouting, you open to quick, informal construction without the planning that comes with more reliable high lift grouting. You have more time to inspect and agree on the adequacy of rebar placement, cleanliness of the grout cells and grouting procedures/sequence. Self consolidating grout (SCG) works well for higher walls if the code in effect is new enough to permit it.

Greater spacing of heavier rebat usually can give you more accurate steel placement if it is critical.

Dick

 

[scottiesei]

How about any section of ACI530 1.13? How would the mason "prove" that he met the standards for lapping, clear distance, etc. as previously stated. That is why the jurisdictions' around here (Florida) typically inspect the walls and reinforcement before they allow grout pour.

 

[scottiesei]

And......
Part 3-Execution
3.2E - "Place reinfrocement and ties in grout spaces PRIOR to grouting"
That's page S-19 in the ACI530-05

 

[SperlingPE]

scottiesei

ACI 530-05
Commentary.....
pg. SC-18
3.2 E.

Loss of bound and misalignment of the reinforcing can occur if it is not placed prior to grouting.

 

[csd72]

scottiesei,

when something like this happens it is not up to you to prove that he is wrong, it is up to him to prove that he is right!

 

[scottiesei]

I agree, just trying to help a brother out!

 

[archeng59]

I'm not at work right now to verify this, but I believe theACI 530 specification section requires that the bars be placed before grouting operations. Also, the ACI 530 and the IBC Chapter 17 requires special inspections of rebar placement before grouting and that the special inspector observe the grouting operation for load bearing CMU. These are building code requirements and not to be ignored at the discretion of the contractor. Regardless, if the rebar is placed after the grouting operation and the bars must be hammered into place, that is poor workmanship.

 

[Galambos]

from my field experience, it sounds to me like the mason was caught grouting without reinforcing the cells and came up with a quick excuse. this has happened to me on two occasions.