×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

early concrete loading

early concrete loading

early concrete loading

(OP)
On our structural general notes page for our typical jobs, we usually put a note that says do not load concrete members before 14 days and before their specified 28 day strength is obtained.  I have a contractor asking if he can load it before the 14 days.  Is there an ACI document that I can reference to find a good answer for his request?  ACI 347?  Is there general industry practice for this?

RE: early concrete loading

Probably not, but the earlier you load it the higher the creep deflection will tend to be.

Just say no, they tendered for it as is with the notes stating that, if they didnt read the notes then thats their problem.

RE: early concrete loading

you can strip formwork earlier not sure about loading. We have loaded ground slabs earlier. But these were lightly loaded. Can you carry out quick design check on the proposed loading, advise him of min strength, say he has to do cube tests to prove. that should put him off.

RE: early concrete loading

In seven days ordinary conc. should attain it's 75% of specified strength. Contractor can load it to some percentage (say 25%) of it's full capacity so that construction can proceed. Make sure to give this info in writing and make him responsible for any outcome of "his" DEVIATION from standard procedure. Also you should have 7 days test result available from same job.
When you write like this, probably he will like to wait ! ! !

RE: early concrete loading

Another way to handle the situation is to tell the Contractor something like this: "Since you want to do something that is not allowed by the specs, YOU provide the documentation to support your request."

As an Owner, we have used this many times solve this type problem. Most of the time that is the end of the matter, but every now and then a Contractor will come up with a way to do what he wants that is acceptable and benefits the project.

www.SlideRuleEra.net idea

RE: early concrete loading

As someone who does a lot of construction engineering, in most cases it is the contractor's engineer who deals with situations like this, unless there are very specific concerns with the proposed situation. I would  do as suggested by SlideRuleEra and hand the responsibility back to the contractor.

RE: early concrete loading

I get asked this question quite often. My standard reply is that either a high early cement or an accelerator needs to be added to the mix. Then a compression test on a three day cylinder should be made. After I have had the opportunity to review the results of the test break then I will decide if it is acceptable to begin loading the concrete.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources