×
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

Post Tensioned Slab Failure. test recomendations??

Post Tensioned Slab Failure. test recomendations??

Post Tensioned Slab Failure. test recomendations??

(OP)
I'm working on a building that was built in 1970. It has a basement post tensioned slab. The building is near the sea, so in high tides the water table is higher than the slab. The slab was designed for upward pressure, but apparently not enough because the slab has been leaking since the 1990's after some severe weather caused the water table to rise above what the slab was designed for. We think the slab has failed in punching shear.

What I need to know is this:
Is there any tests I can do to measure what the hydrostatic pressure is during high tides. I was thinking of some kind of tube placed through the slab into the soil. With this I can measure the head of water.

I'm also interested in any suggestions of how to increase the punching shear capacity of the existing slab at the columns.

Any ideas/suggestions would be greatly appreciated.

RE: Post Tensioned Slab Failure. test recomendations??

My suggestion would be to figure out what is currently in the slab design, figure out the soil pressure and find out how far off the slab is.

I don't know what is done in industry but a simple manometer epoxied to a tap drilled into below the slab can tell you what happens at high tide.

From there you can look at what is done to design slabs for punching shear in the first place.  You could use a steel bearing plate to increase the perimeter and therefore the shear capacity.

You could epoxy some rebar or similar in diagonally drilled holes which cross the shear plane perpendicular.

Really all sorts of repair or redesign options exist.

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