IBC Special Inspections - process 2

[JAE]

We have a project within our city where the IBC 2000 is adopted. On our plans, we indicated which special inspections were required per chapter 17. The plans call for the contractor to coordinate with the special inspector (i.e. notify the S.I. when work will begin so special inspections can be performed).

We just received a report from the project manager (an independent firm hired by the owner to oversee their projects....i.e. the owner's agent). The report is from the special inspection firm who completed the form last May on concrete masonry walls.

These are CMU walls that are load bearing, and also serve as shear walls for the structure. They are reinforced and grouted in spaced cells.

The report shows that all the "periodic" inspections were completed but that full time (continuous) inspections were not provided for grouting. In fact, the report states that they arrived at the site and some of the walls were already grouted. It goes on to say that the contractor was wet-stabbing bars into the grout so they checked "NO" on the boxes dealing with lap splices and inspection of rebar before grouting.

Now the project manager is asking us to comment/review the report (which we did not get in May). My question is:

What can be done at this point to ensure the wall is "acceptable"? The CMU walls are all completely enclosed by exterior veneer and interior finishes. The inspections indicated a questionable practice of wet-stabbing and now we as EOR have to comment on this.

The IBC has no apparent provisions for responding to missed inspections. Suggestions?

 

[VoyageofDiscovery]

Hi JAE,

This occurred to our firm when I was a young lad and we were the designers and inspectors. The principals told me at the time they "could not afford" to have an inspector at all times. As explained, this is the sorry state of affairs when everything is lowest bid. Federal/state jobs usually go to the lowest bid as you well know.

This was a school and the principals had a suspicion that the contractor had not placed reinforcing in a constructed gymnasium wall. We went to site and broke a few cells in the wall and low and behold, minimal rebar. By this time we couldn't demolish this wall without serious implications, though I think if it had been up to me I would have had them demolish that wall.

Anyway the long and short of it was that the firm then went on to design some cockamamy (my opinion) retrofit under the bleachers.

So in my humble opinion, no inspection, no good, shore the joists and demolish. I wouldn't want this on my conscience as well. Oh I have since moved on.

Regards

VOD

 

[jike]

I would tell the Owner's rep., in writing, that the inspections did not fully comply with the specs and the building code and explain why. At this late date, it is not possible to fully evaluate the structure with an incomplete report.

Recommend that additional testing/inspection be done to assure that the building was built in accordance with plans and specs. Work with a testing company to develop this plan. Try to minimize the amount of destructive testing required.

I would contact the local or State building authority and explain the situation. Tell them what you propose to ask for and see if this is acceptable.

 

[Ron]

JAE...I agree with jike. Go on record now.

Some special inspections can be performed after the fact, but reinforced masonry isn't one of them. There are several nondestructive methods that can be employed, though since finishes are already in place, some destruction will be necessary. One method you might try is infrared thermography. If you are able to put a DC current into the rebar, it will heat it up slightly and show nicely on a thermogram. Fairly often it will show with just a good day of sunshine on the wall then check it as the sun goes away. Residual heat in the wall will show filled cells, cavities, gross underconsolidation, and rebar in many cases.

The codes have not yet become so universally known that these issues have died. Inspection is one aspect that must be properly scoped on the front-end, the owner must be made aware of the need for full-time observation during certain phases of the project, and the contractor must be informed of the need to coordinate the services. Such inspections are first accountable to the public (building department) and then to the Structural Engineer of Record. Without them, the SEoR cannot confidently sign off for the project. Unfortunately, this issue comes up way too often.

 

[JAE]

Thanks for the replies...

Is there any industry acceptance for wet-stabbing bars in low-lift grouting of CMU? If the bars are of a set length, and the lifts are of a set height, then the amount of lap splice can be controlled. The grout is usually quite liquid (8" slump) so it seems like it could work.

I don't allow wet stabbing of rebar in concrete, but in grout in CMU is it common/acceptable, etc.?

 

[VoyageofDiscovery]

Hi JAE,

Were the footing dowels inspected?

Regards

VOD

 

[VoyageofDiscovery]

Wrt wet stabbing, you would have to confirm the bar location within the cell.

I don't see a problem wrt grout to bar bond.

Regards

VOD

 

[jike]

I would be concerned about the exact position of the rebar in the cell. Did you specify the use of rebar positioners?

http://www.heckmannbuildingprods.com/PRebar.htm

If the rebar was cut in the field, I would be concerned about the correct lap.

I know of no industry standard preventing the wet stabbing of vertical rebar.

 

[JAE]

jike - we did specify bar positioners and also referenced ACI 530 which only prescribes setting rebar in place prior to grouting....with no mention of wet - stabbing.

In fact, I can find no reference anywhere that discusses or allows wet-stabbing. Every reference I find speaks about setting rebar first, then grouting.

 

[jike]

I found what you are looking for in ACI 530-99, 3.2E (S-20). Also see Commentary SC-17. It talks about possible loss of bond and misalignment, if reinforcement is not placed before grouting.

 

[dicksewerrat]

Has the contractor been served with this report? Was there retainage on the project? I think you are trying to cover his butt.and he should be held accountable for what he did or didn't do.

 

[JAE]

I'm not covering anything - we were simply notified by the project management company that the inspector reports were questionable. We have been asked to respond to the situation. We are currently headed toward further testing and investigation (non-destructive and possibly destructive) to verify the condition of the rebar in the wall.

 

[Corn]

I think the rebar could be x-rayed in situ. While outside the scope of most normal building special inspection. I have had large x-rays taken using portable radiation sources and film placed on the opposite side of the object of interest. I also like the thermography concept but I think if you wanted to know rebar location within the cells a couple of x-rays from different angles could tell you.

 

[gsfitzsr]

JAE,

Infrared surveys should reveal where grouted cells are located as well as horizontal bond beams, tip caps, etc.

I've been sucessful doing this in the Houston are for some time. If you need more info let me know.

Greg