×
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

Construction Joint Testing

Construction Joint Testing

Construction Joint Testing

(OP)
Hi,
I have a situation here where concrete was poured in a manner that created an 'unplanned' construction joint (in a suspended beam/panel slab).
Part of it runs over a wall support and I want to ascertain the quality of that joint in terms of the bonding and concrete strength through the joint (which is inclined at about 45 degrees) in that area.
I'm thinking of taking some cores for visual inspection and load capacity assesment.
My question is, are there any standards or literature out there which might guide on what to look for and maybe even some testing methods?

Thanks,

RE: Construction Joint Testing

Basically I would explore the ability of what built to pass the stresses to one side and the other side of the interface for a range of friction factors in some kind of friction shear scheme.

I think it would be a truly bad joint the one that unable to behave reasonably upon monolithic concrete if well reinforced; in fact, some kind of deteriorated joint, a crashable, able to freely open or greased one, typically. For most other situation ever a poorly executed cold joint should behave at service level in quite akin form to monolithic.

Another focus of attention is that water won't be able to access the rebar through the joint.

http://ieeexplore.ieee.org/Xplore/login.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F7781%2F21383%2F00991834.pdf%3Farnumber%3D991834&authDecision=-203

 

RE: Construction Joint Testing

(OP)
Thanks for the reply.
I see what you mean regarding the friction mechanism as a method of stress transmission. I'll do some numbers on that. I believe the friction co-efficient of concrete generally floats around 0.33.

I'll also include a range adhesion values to model the non-mechanical bonding along the joint.

Thanks for the link as well, I'll definitely have a read of that paper.

RE: Construction Joint Testing

I would recommend not pouring new concrete over a 45 degree slope on the old concrete. I would cut it vertical, check shear stresses, add shear friction steel if required and continue the pour.

I am a little fuzzy about what you mean about part of it over a wall but when you are done the stresses have to work for the proposed condition and the surfaces should be vertical, clean and sound.

RE: Construction Joint Testing

(OP)
Ron,

Thanks for the reply.

With regards to the wall, I meant that there's a shear wall underneath which is also supporting the slab.

Just out of interest though, what is 'friction steel'?

 

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