×
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

Plain Concrete Grade Wall - Slab Detail

Plain Concrete Grade Wall - Slab Detail

Plain Concrete Grade Wall - Slab Detail

(OP)
Client would like to replace my 2' wide X 1' thick concrete footing and my 8" thick x 22" tall concrete grade wall with a solid rectangular plain concrete grade wall 2' wide x 34" tall.  They would also like to try to pour the slab at the same time and use bent dowels at the slab to grade wall transition.

I am not so concerened about the grade wall as there is virtually no load on it because of the metal wall sheeting above and it is serving mainly as a frost break but I am concerened about the transition to the slab and it being one continuous pour.  Even with the dowels I am concerned about cracking as the slab wants to shrink and is restrained by the grade wall.

Has anyone used a detail like this and have any thoughts or recommendations?

Thanks!

RE: Plain Concrete Grade Wall - Slab Detail

The slab will certainly shrink and crack.  In order to prevent this cracking, there must be provision for separation of the two or a way for the slab to slide relative to the footing.

RE: Plain Concrete Grade Wall - Slab Detail

The grade wall potion of the sketch seems mighty hefty.
 

RE: Plain Concrete Grade Wall - Slab Detail

(OP)
Oh it is.  I wouldn't have a problem going thinner for the reasons I mentioned earlier and I will tell them this before they construct but this is the description they gave me.

RE: Plain Concrete Grade Wall - Slab Detail

Their detail was terrible.  Not only for causing shrinkage cracks in the slab, but those bars around the corners violate good practice, as if they straighten, they break out the corners.

Suggest rather than just a cold joint, a layer or two of plastic would help to allow the slab to slide and reduce restraint cracking.  However, if it is necessary to provide tiedown to the footing, crack control would be a secondary consideration.

RE: Plain Concrete Grade Wall - Slab Detail

Are there concerns with cold penetrating the slab as have been expressed in other similar posts?

RE: Plain Concrete Grade Wall - Slab Detail

They were trying to save money by limiting forming and the number of pours, saying the extra cost of the concrete was less expensive.

Personally, I would limit possible water intrusion at the exterior here by setting the edge of the slab in by the width of the exterior wall above.  This will require extra formwork.  Otherwise, depending on your locale, you could be looking at frost heave between the bottom of the slab and the strip footing.  Just a thought...

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

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