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Rebar Spacing Issue
3

Rebar Spacing Issue

Rebar Spacing Issue

(OP)
I have a situation were it has come to light on the job I'm doing inspection work for that the contractor placed (3) #5 rebar all in one plane at the bottom of a standard 8" stem wall with only a max of 5/8" spacing. Per ACI-318 the requirement is a minimum spacing of 1". I'm not the engineer for this project, I'm an owner's rep, but it appears that the CM is going to have the design engineer sign off on the situation. Since ACI-318 is the building code is it right to allow a sign off of code requirements. Am I wrong to be completely opposed to a sign off in this situation. I'm of the understanding that the concrete will separate aggregate and cream and not bond well to the rebar and could create voids ann/or a weak spot in the concrete in this area, so I would think this would be a critical issue. Please give me any advise or perspective on this issue.

RE: Rebar Spacing Issue

Check your contract, but as an inspector, I believe you are responsible to observe and report. Do this well and then it is up to whoever you report to take the responsibility from there. In a perfect world.

RE: Rebar Spacing Issue

As we've discussed in the past, it is generally the designer's prerogative to say yay or nay to these kinds of things.

For stem/frost walls, the intent of concentrated longitudinal reinforcing is generally to provide nominal flexural capacity in the wall/footing assembly so that it can span over soft spots in the soil that may occur. Since there's really no defined bending moment to be designed for in this situation, it's understandable that the designer may not be concerned about the loss of bond in the concentrated reinforcing.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Rebar Spacing Issue

Well, there should be a strip footing (12" wide minimum) below the stem wall, and the #5 bars should be in that strip footing, not at the base of the stem wall.

Mike McCann, PE, SE (WA)


RE: Rebar Spacing Issue

(OP)
My major concern is due to the aggregate being strained out and getting pure cream underneath having a dead/ weak spot in the concrete.

RE: Rebar Spacing Issue

I'm a little confused here. Is this a localized problem? If you observed this situation and it doesn't comply with the contract drawings shouldn't you have asked to contractor to move the bars to where they needed to be?

RE: Rebar Spacing Issue

And if it is at the bottom of the wall, I'm wondering what good the bars do structurally. The SE on the project can certainly review the situation and determine if the loss of concrete aggregate or quality below these bars is an issue that would affect the performance of the wall.

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RE: Rebar Spacing Issue

It doesn't sound like that big a problem to me from the info i have. you have a good understanding of what the code says and the materials used, but it sounds like you might find a lot of redundancy and unaccounted safety factors if you were to analyze the structure. you have to know whether that rebar is needed at all to judge and without reverse engineering off the construction documents, you won't get there unless it is a major red flag detail that makes no sense.

There was a comment "If you observed this situation and it doesn't comply with the contract drawings shouldn't you have asked to contractor to move the bars to where they needed to be?" posted which wasn't meant to harm and i'm not judging the writer on it because it is a very common statement... but as a manager of inspectors for over a decade, this is the most dangerous concept in inspection. usually there is 1 independent inspector (and many times just a guy earning ~$15/hour) to the entire construction team and realtime construction is fast-paced. It is very easy to internalize the 'it got pass me or i let it go, so i have to live with it.' Inspectors are not Referees for a Game. The door is always open to review after the concrete is hard, and in most cases the addition of more materials is what makes that defect that 'YOU signed off on!!!' obvious. it pisses people off and doing it all the time would leave one unemployed, but every inspector needs to have the courage to point out a defect when they are aware of it. Study the plans, understand how they are building it, and always make sure the contractor inspects their work first.

RE: Rebar Spacing Issue

(OP)
For the record I was invited to a rebar inspection on Friday afternoon. Was informed they were not ready. Appaerently on Saturday they conducted a rebar inspection without me and once on site on Monday they had set the exterior forms, so there was no good way to see those bars. For the record there are 4 layers of inspection before me.

The situation existing throughout the entire perimeter of the building. The contractor put the (2) continuoius bars and the regular middle reinforcement wall bars that were spaced at 12"o.c. and put all 3 in one line and spaced them using the #5 vertical bar and a piece of #5 for the other gap. This building was placed in concrete. When we went to the next sturcture all the sudden everyone is calling foul when they have the same detail and situation and they placed both the top and bottom bars that way. At that time they sent RFI's and followe the correct proccess. Respaced the middle bar, so that everything was correct and placed concrete. As soon as everyone called foul I said hey wait they did that same thing on this building why aren't we worried about that. So right away the question was asked and the request want made for proof of how the 1st buildings rebar was set. 6 weeks later they finally admit it was done incorrectly and now they want to have the designer sign off on issue.

RE: Rebar Spacing Issue

darth

I don't quite get your statement as it seems like you do not agree with what I said. If someone sees something wrong they are they not to notify someone to make a correction? Especially if it is an inspector (which the OP does not appear to be).

As I suspected, this problem popped up during construction and come to find out, was applied to other areas. In this instance, it's up to the EOR to make the decision if there is a problem or not. It seems like the foundation crew isn't that experienced (which usually sends shivers up my spine).

RE: Rebar Spacing Issue

SteelPE,
Yes and no. It depends on the role of the inspector. A lot of 3rd party (or independent) inspectors don't have the authority (unless given to them in the construction documents) to tell the contractor that they cannot do something. Regardless, the deficiency should be well documented and reported to not only the superintendent and foreman, but also to the inspector's superiors via his/her report.

If the independent inspector is acting on behalf of the AHJ, then the contractor must comply or face a failed inspection. In my jurisdiction, many times the 3rd party inspector will be on site monitoring the construction activities while a county inspector will come and inspect such things as steel reinforcing.

RE: Rebar Spacing Issue

What is the actual aggregate size? And can that size be changed now - before the pour?

If already poured, how "thoroughly" was the concrete rammed past the mesh (the bars) at the bottom?

RE: Rebar Spacing Issue

3/8" pea gravel would work...

Mike McCann, PE, SE (WA)


RE: Rebar Spacing Issue

The EOR (and the local code enforcement authority, if involved) has the responsibility to decide what is acceptable. The EOR has the authority under ACI 318 to design outside of prescriptive code requirements and allow exceptions.

As to whether the reinforcement is adequately embedded, from a generic perspective, my answer would be "maybe." There are a multitude of reasons why rebar needs embedment and having a wide plane of nearly solid reinforcement is a bad idea. But in this case, for such a narrow installation with the rebar concentrated in the center with adequate distance on each side (between outermost bars and the forms, the wall will likely functions properly. Aggregate was probably able to flow around the sides of the longitudinal reinforcement, and only needed to move laterally a couple of inches below the rebar. If an engineer was concerned, he could easily have the contractor excavate at a couple of locations and directly examine the extent of consolidation.

It is the role of an inspector to examine and report, so that the designer, contractor, and/or owner can make informed decisions about accepting the work, requiring rework, and needing better QC on future work.

RE: Rebar Spacing Issue

(OP)
The aggregate it 3/4". I'm the owner's inspector and I've done my inspector's job of reporting and supporting it with the spec. I'm a Structural Engineer liscensed in the state I'm working. The CM highered both the designer and the contractor, so to a certian extent this is a design build situation. Because of my professional backgorund I'm being asked to give my proffesional opinion to the owner if the they should consider taking a sign off from the engineer of record on this issue. My basic opinion to them has been that the violoation is of ACI-318 which is the building code reference, so therefore they should not be accepting any signoff when the work does not comply. I understand there is latitude when working with specification violations and different interpretation of the drawings and the engineer figuring out if what was installed is adequate. But it is my personal opinion that any owner should not be accepting any structure that does not meet any porition of the building code. Is this too rigid of a view? I'm really looking for feed back on the back end of this problem. As an inspector I did what I was suposed to, but becasue of my unique situation of being a structural engineer on the flip side I'm looking for some perspecive on my opinion of the overall idea of having an engineer sign off on a code violation.

RE: Rebar Spacing Issue

So what are all of these "Program of Structural Tests and Inspections" I fill out to be in compliance with Chapter 17 of the IBC? So we have inspectors onsite who are doing nothing other than putting findings into a report and passing them onto the EOR for review after the concrete has hardened.

RE: Rebar Spacing Issue

Greatone,
I would tend to agree with you that a structure not built in compliance with the building code is not acceptable. As we are all so fond of saying, the building codes are the "minimum" necessary requirements for design. Anything below minimum is sub-par work, IMHO.

Have you seen any concrete break reports for the concrete in question? Have the forms been stripped where you can actually view the area of the wall?

RE: Rebar Spacing Issue

Quote:

But it is my personal opinion that any owner should not be accepting any structure that does not meet any portion of the building code. Is this too rigid of a view?

Yes - this is too rigid.

As TXStructural has indicated above, the EOR has the knowledge and ability to investigate the situation and determine if:
1. The technical code violation affects the public safety and welfare, or
2. if it affects the value of work that the owner paid for.

Those are two different things. But both are under the authority, ultimately, of the EOR, not the text of the code, in my view.

An example of this is the post above:
It may be (I'm not sure) that the bottom bars in the wall are not used specifically in stressed zones but may simply be an excess of steel in the bottom of the wall.
In this case the intent and purpose of the code provision just doesn't matter in any way to the integrity of the wall, or its function.
But the EOR would know this. The code provision doesn't.

The EOR could evaluate any and all negative effects of the poor spacing for either the code intent or in terms of the value to the client.
It is their call in my view.

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RE: Rebar Spacing Issue

Quote (Greatone76)

I'm really looking for feed back on the back end of this problem.

Greatone76 - I am going to give you what I hope you will accept as true constructive criticism. All of this is strictly my opinion, but based on relevant experience.

I am a long-time, retired Owner's Representative (By that, I mean a permanent, full time, direct employee of the Owner - not some sort of "contract employee").

Quote (Greatone76)

Because of my professional background I'm being asked to give my professional opinion to the owner
Unless you have been explicitly instructed otherwise, on that job site you are the Owner. You are "not seeing the forest for the trees". You have an Engineer of Record, a Construction Manager, a Contractor, and "4 levels of field inspection". It is obvious, to me, these people are NOT working together - that is the real problem. By concentrating on the nitty gritty details, you are allowing others to marginalize your authority and get away with inferior work. Quit worrying about the rebar - there are plenty of others on the job site who (should) have that responsibility. Your obligation is to report to your Employer the dysfunctional organization you are witnessing, and if authorized to do so, take the steps to straighten things out. If you want, I'll be happy to discuss exactly how to do this, without being a dictator. It is not a straightforward road, but it DOES work.

Now, off the soap box, the next step is yours. No problem for me to just be quiet. Good Luck.

www.SlideRuleEra.net idea
www.VacuumTubeEra.net r2d2

RE: Rebar Spacing Issue

(OP)
SlideRuleEra I have been able to convey the big picture of the problem to the level above me and they are attempting to get resolution in the levels above them, but as we wait we are left to debate the individual issues. I don't see how I can private message you otherwise I'm quite interesting in discussing my exact situation and learning the approach you would take to get the big picture across to the owner, because at this point it appears the full message might not be getting across well enough.

RE: Rebar Spacing Issue

I, for one, would love to hear SlideRule's recommendations. If it wouldn't represent a breach of confidentiality, please consider having the discussion here.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Rebar Spacing Issue

Ditto Kootk! The floor is your's SR!

RE: Rebar Spacing Issue

GO76 - Don't worry, I'm not talking about private messages... instead, right here as KootK and CELinOttawa indicated. I don't mind being critiqued myself. After seeing a post from you, I'll want some time to compose a well thought out response (say a couple of hours, or so). I'm in the US eastern time zone, hopefully there is not significant difference where you are. Its a little late today to start. I'll make my initial recommendations in the morning (Saturday). Weekends here on ET are a good time to begin, usually site usage is down.

www.SlideRuleEra.net idea
www.VacuumTubeEra.net r2d2

RE: Rebar Spacing Issue

GO76 - You may not have noticed, but I just demonstrated the first rule of being an Owner's Representative (OR)

Don't Get In A Hurry.

"Expediting", "Job Emergencies", "RFI's" etc. are for the Engineer (EOR), Construction Manager (CM), and the Contractor. The OR's responsibility is to keep up with the job's "big picture" and to get involved only when absolutely essential, and ideally never. There is one exception to this, we'll get to that later. Jumping into solving day-to-day situations is a sure-fire way for the jobsite personnel to keep you distracted from effectively doing your "real" job. On your project, this whole situation is way out of control.

You have got to convince your management to provide you with their full confidence and support. The way to do this is to provide timely, accurate, written explanations of what you are observing. The trick is to voluntarily give this same report to appropriate project personnel at the same time. You do not want a reputation as a "spy". I expect that your management are intelligent individuals who are skilled in areas like sales, manufacturing, transportation, accounting, finance, etc... but not engineering / construction. It is up to you to use your engineering education and experience to "translate" the technical and construction management situations (good and bad) that you encounter. The translation has to be to terms that are accurate yet composed using excellent grammar and spelling in terms that will be meaningful to non-engineers. We will get back to how to gather, prepare and present this information. After you obtain management's confidence you need to demonstrate the usefulness of you having what we used to call "full disapproval authority" (Really, I am not making this stuff up.) As issues come up that will (or should) significantly affect the contract price, you should be informed in advance. If you don't agree with the change or the proposed price you should be able to immediately freeze the change process until you can brief your management. Notice that this is for disapproval only, you can NOT approve any change - that is your management's decision. It is also an excellent excuse to keep project personnel from putting undue pressure on you to allow the change.

Now, let's address your latest posting:

Quote (Greatone76)

I have been able to convey the big picture of the problem to the level above me and they are attempting to get resolution in the levels above them, but as we wait...

No. Why are you waiting? Continue to do the job of obtaining information (which will not be good) and making it available to your management. You have got to impress management that "time is of the essence".

Quote (Greatone76)

...we are left to debate the individual issues.

No. The word "we" does not include you. This is for the CM, EOR and Contractor. Your job is to see if they can effectively resolve these issues. If they can not, then there is more evidence of a dysfunctional project.

That's enough for now. Take your time, read through it and see if you can agree. If not, we can discuss our differences. If you do accept it, we will move on.
SRE

www.SlideRuleEra.net idea
www.VacuumTubeEra.net r2d2

RE: Rebar Spacing Issue

@steelpe
i wasn't taking issue with what you said, or you for saying it. There will always be the question you voiced at the beginning of these issues, and it is best that Inspectors are ready to have those kind of conversations. The 'inspector showed up, didn't say anything, and reported badness after it was too late' is a common narrative , but i would argue the vast majority of the time it is not because the inspector made a conscious decision to Not Inform the contractor when they became aware of it. We actually agree on the fundamental level "If someone sees something wrong, are they not to notify someone to make a correction?".... i'm just reinforcing to inspectors who would read this thread, that this sometimes inconveniently occurs after materials are down and you still must notify.

@greatone76
sorry to imply you didn't understand the loadings... most people that do rebar inspections for the Owner i've come across aren't SE's, and the inspection business usually elbows individual development of structural design to the side. all IMHO and in regions i've worked. on a different point... just wanted to throw out there that it is not unusual in our industry for something to be *acceptable* when it is as-built, but not acceptable to build it again that way. it's not logical, but it's not unusual in the normal jobs where the EOR is separated from the CM. on the other side of the coin, the worse job i've ever worked was a CMAR design/build with a spineless EOR (which turned into 5 different EORs quitting over the construction phase)... so just hearing CMAR makes my stomach turn and puts me on DEFCON3.

RE: Rebar Spacing Issue

(OP)
@darth
No issues. I'm in a really odd situation doing what I'm doing and having the knowledge and education I have. It puts me in some awkward situations.

@slide
I'm onboard with everything you are saying. The piece that is different and killing this project is that there is multi-layer management I'm reporting to. I have effectively communicated the dysfunction of the project to the people I report to, but the big picture fix project power is above that layer I have convienced of the problem and that next layer is being very slow to do anything. I have continued to provide the evidence that this is a dysfunction project. It appears at this point that the next layer up is in the position of not doing anything which leaves myself and the bottom layer I report to debate the corrective action proposals and sign offs from the CM and thier designer. For example we recieved calculations for capacities from a code table for a certian capcaity, but the loads in the calcs are for a completely different situation. And they are trying to pass this calc off as proof they don't need something that was not installed by the contractor. I've run the calcs using the load on the plan and fasteners submitted and conclude they need what they didn't install. So we are seeing evidence that the CM is willing to provide bad engineering information as a sign off. And we are seeing that the EOR appears not to have done the original due dilligence and is not doing thier due dilligence on the signoffs. Which leaves us to debate if any of the things we are getting signoffs on are legitimate. Going back to my original question about this half an issue with rebar spacing being something reasonable to get a signoff on. I would not in general sign off on this type issue, but I'm looking for some perspective to know if advising up the chain if this would be an acceptable issue to dig our heels in or something to just let go.

RE: Rebar Spacing Issue

If in this specific case, the rebar placement, is the only thing you are requesting opinions on then as Darth mentioned, the as-built condition is likely acceptable in most engineers' minds, however it is something that should be code-compliant on subsequent builds. Just because it was done wrong once and deemed acceptable does not exclude it from being done correctly the next.

For the project as a whole, I think there has to be a point at which you dig in your heels, however in order to back up that stance you need the documentation of the issues and your attempts to remedy them (that includes just passing the news up the ladder,). If as you've mentioned the management layer 2 above you seems to be dragging their feet then at some point (this point will differ largely between people) you need to skip a rung or two on the ladder, voice your concerns (include your back-up documentation showing you did everything in your power before jumping rungs).

If life-safety is an issue, the last stop would be the building authority in my mind.

RE: Rebar Spacing Issue

Greatone76 - Ok, you have convinced me that you are in the middle of a situation way too big for you to turn around by yourself. There is no point, at this time, my continuing with Owner's Representative tips. However, what you describe is hauntingly similar to what happened in our company some years back. I'll give an outline of that story and one of the outcomes that may apply to you.

Another (non-technical) branch of our company was given the job of managing design / construction of a major office building for use by the company. Everyone in our office was puzzled why we were intentionally left out. Over the next year or so, the work progressed. Very little information was being released to company employees on progress. Just by looking out our office windows it was obvious that many problems were occurring, but work was proceeding regardless.

Finally, construction abruptly hauled with structural work about 90% complete,and job site was effectively abandoned. At this point, our office was quietly brought into the project. Turns out there was widespread negligence by the CM / EOR, gross negligence by the Contractor, and criminal graft and corruption on the part on one individual in our company's executive management. While lawyers worked on financial & criminal matters, our office was responsible to determine if the structure could be salvaged and if so, proceed to do so. It could, but with an unearthly amount of demolition, rework and repairs.

My point on telling this story is that one, and only one, organization originally involved came out of the years of legal proceeding with a clean record. From the beginning of construction, the contract inspectors had observed the substandard work and had explicitly pointed it out on every report they made. Because of their low status on the project, they never took any drastic action outside of reporting their findings.

Based on this, I suggest that you not stand in the way of any individual defect you find... however, keep delivering written accurate information and your professional opinion on what you observe.

www.SlideRuleEra.net idea
www.VacuumTubeEra.net r2d2

RE: Rebar Spacing Issue

Interesting anecdote about the only person to come out of that without reprimand (or worse I gather). I'll definitely take your advice to heart.

This also makes me glad to often work on smaller projects.

Maine Professional and Structural Engineer.
(Just passed the 16-hour SE exam, woohoo!)

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