×
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

Uneven interior slab-on-grade

Uneven interior slab-on-grade

Uneven interior slab-on-grade

(OP)
The situation is inside a 10-year old addition to a municipal building in central PA. A large conference room slab-on-grade consisting of nine 20'x20' "quadrants" separated by 2 construction joints and 2 saw-cut joints. No expansion material was observed anywhere within the placement area and no dowels, reinforcing steel or WWF was found during initial investigation. The center 3 quadrants have apparently "heaved" shortly after placement, because some flash-patch material was used along the construction joints prior to the original flooring installation. Subsequently, additional "heaving" of the center sections has created a 1/4 to 1/2 inch difference in elevation between sections. All 3 center sections have raised the same amount, and the 6 outside sections are all at the same relative elevation. The 4 to 5 inch thick slab is on a vapor barrier of plastic above minimum 6-inches of #57 stone on compacted clayey subgrade. Investigation of in-situ subgrade conditions is on-going but... what could have cause the center sections to be "jacked up" above the outside sections?

RE: Uneven interior slab-on-grade

What leads you to you think the center has gone up rather than the sides going down?

RE: Uneven interior slab-on-grade

(OP)
We have checked elevations with adjacent slabs outside the room in question and the side slabs are the same elevation throughout - the center slab is consistently higher throughout.

RE: Uneven interior slab-on-grade

You need a geotechnical investigation. Elastic rebound, chemical expansion both can be the cause. To discern the likelihood of any cause the more the data the better. Even if settlement was the cause, the geotechncal study would be warranted, so press ahead.

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