My very first "concrete pour"

[GalileoG]

I will be going tomorrow on my very first "concrete pour." They are pouring strip footings of a 100’ wide 3 storey town-house. I was on site today to inspect rebar location, strip footing dimensions, cover, etc. I found issues with the cover where the longitudinal bars where more than 7” from the face of the form (too far in) and also terminated too close to the end of the form. Also, there is no overlap of longitudinal rebar where the strip footing turns at right angles. Also, electrical ducts were too close to the underside of the longitudinal rebar.

I am hoping that when I show up tomorrow, all the issues I raised were addressed and the corrections completed. Given that I was there to raise these issues only noon today and they are pouring tomorrow, I am not so sure they would have enough time to make these changes, but then again I am not sure how long everything takes on site.

My question is: What sort of questions can I expect tomorrow? What should I be looking out for? When should I say “halt the pour!” without being unreasonable?

ANY and ALL advice would be appreciated.


Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[Ltwine]

"We need to put a cold joint somewhere, where it should be?"
Vibrate on rebar mat to help concrete flow - STOP
Broken chair/block so rebar mat lays directly on form - STOP
Excessive slump - STOP
.....

 

[hokie66]

Check to see that all items in your site instruction have been corrected. If not, notify the site superintendent immediately. Look for other issues which have developed since you were there (electricians, plumbers, etc. can do a lot of mischief in 12 hours).

When you say the electrical ducts were too close to the underside of the longitudinal rebar, I assume you mean too close to the top bars. You don't want ducts under the bottom bars.

Now look for items required for the concrete placement and inspection. Who will do the sampling? Slump apparatus? Concrete thermometer if required? Vibrators?

Find out who is in charge of maintaining the reinforcement where it is supposed to be. Start with the assumption that big footed concretors will do their best to displace it.

Keep your eyes peeled and maintain an affable demeanour unless you don't get cooperation.

 

[LSPSCAT]

Remember...we "place" structural conrete...you "pour" your backyard patio!

Its a town house so it might not be that big of a deal but on large pours for structural concrete always keep track of the trucks...how many trucks does the plant have dedicated to this job? Schedule? How long have they been sitting on site? How much water have they added? Is it the right mix? Simple things usually cause the biggest problems.

 

[cvg]

We typically have an inspection card that must be completed and signed off by the inspector before a pour is scheduled. that avoids the last minute inspection while the mixer trucks are on their way to the site. Good luck and hope the contractor has everything ready to go tomorrow morning...

 

[JAE]

Take photos...nothing more un-nerving for a contractor as when the engineer snaps photos of rebar in the wrong place.

 

[cvg]

given that there is a high probability that something will be wrong since they may not have had time to fix the deficiencies - be prepared to document them, ask the contractor to correct them and if he doesn't document them fully. Sign your inspection report listing the deficiencies, have him countersign it and give him a copy for his records.

 

[BlastResistant]

Check the concrete tags. Make sure it's the right mix design and that it's not more than 90 minutes since batching before the concrete is placed.

 

[mmillerpe]

I am not sure in what capacity you are working on this project, but you should be very clear prior to going to the site whether or not you have the authority to stop a placement.

As an inspector your job would be note non-conforming items and notify the contractor, SER, and building inspector, and hope that any fixes get completed prior to concrete placement.

As a field technician, you may sample the concrete, and if it is not within spec, notify the contractor who may reject the load.

If you are working as an agent of the owner, you may still have other responsibility and authorities.

In my experience, working as an engineer or special inspector you do not have the authority to stop work.

If you don't have the authority to stop work, you may end up buying a truck of concrete.

The following two clauses can be found in the standard SI agreement between owner and SI developed by CASE:

"The SI shall not be responsible for the failure of the Contractor to perform the construction work in accordance with the Contract Documents."

"The SI shall not have the authority to stop work on the project."

If the contractor decides to move forward being in non-conformance he/she risks having to remove and replace defective work, so generally it is in his/her best interest to correct any deficiencies before they become real issues.

 

[Ron]

Clansman...a couple of technical and legal issues for you to note:


1. If you do not have the authority to stop the pour, don't do it. Tell them you will document and report any deficiencies and they can remove the concrete at a later date...that usually gets them to stop the pour..not you.

2. Grow a set. If it isn't right, tell them it is unacceptable and let them know if they place concrete under those conditions they might very well be tearing it out and doing it over. Tell them you will not sign off for anything that is not acceptable to YOU.

3. Look for the following:

a. Rebar corrections...if not done,raise hell and make sure they know you mean business.
b. If rebar is corrected and they place the concrete, make sure they don't do stupid stuff like try to move the concrete with vibrators, make sure they don't use "jitterbugs", make sure they don't screw up the mix by adding water, make sure the mix as delivered is as designed (slump,air content, etc.).
c. Make sure they have the construction joints clearly set. Make sure they know that they have to cut control joints the same day...not the day after.
d. Make sure proper sampling and testing of the mix are done.

Don't let the lowest common denominator prevail on this...you will be held liable if you are on site and allow the screw ups.

Good luck.

Ron

 

[BAretired]

Clansman,

There is no question that inspection on the job site, particularly when it is your first inspection, is the toughest job of all.

I can clearly remember a few of my inspections in the early days of my practice. Superintendents were not prepared to accept the word of a young engineer. In a few cases, the contractor or sub-contractor became agitated, occasionally threatening bodily harm unless I smartened up. In some cases, it turned out that I was being too fussy about details. It all takes time, and in time, I found out what was and was not acceptable practice.

The best advice I can offer is that, if you have doubts about the way the work is being done, stop the pour until it is corrected or, alternatively, until a senior member of your firm countermands your orders. Each and every one of us needs time to learn what is and is not acceptable, and this only comes with time.

It is far better to raise a stink during the pour and have the contractor miffed at you than to allow unacceptable procedures to continue without saying a word and have questions arise later...when there is nothing to be to correct the problem.

Having said that, I don't think there is much of an issue with the longitudinal bars in a strip footing being 7" from the face of the form. How does that affect the strength of the footing? And, where the strip footing turns at right angles, what is the significance of the overlap of the longitudinal rebar? If it doesn't matter, then let it go. Otherwise, fight like hell!


BA

 

[DWHA]

Remember that if the contractor says we don't have time to correct this, or we do not have enough people to do it that way. It is not your problem. They are to follow the job specs, so read and know the specs. If you see something and do not say anything, then it will become your problem is their is an issue.

As for adding water on the job site, sometimes it is allowable. But you have to check with the plant and see how much can be added.

 

[mbullism]

I know I'm late to the party, hope it went well. Just as above... concrete is cast or placed -not poured.

I'm not sure I'd ever say "stop"... Don't even talk to the workmen... deal directly with the super, and inform him of deficiencies asap. Let him decide to stop- I usually say something like:I'm not telling you to stop, I'm telling you it's not right"

Gets their attention every time.

 

[hokie66]

I guess it is fear of legal issues, but there surely seems to be a lot of timidity about giving instructions, stopping pours, talking to workers, etc. I have often stood in the way of the pump line or kibble until reinforcement was fixed. Workers respect firm action. So far, no one has buried me, and no one has sued me.

 

[darthsoilsguy2]

Take 10-20 photos a day and add 2 to your report. The report will look better and establish precedent that their work may be judged by others after the concrete is placed....

Also, i don't say "Stop work", but only to avoid extra drama. In the end, the contractor elects to stop work whether or not they were influenced by your chit-chat.

i'm sure you did fine.