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!

*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.

Jobs

Coring of existing structure

Coring of existing structure

(OP)
Hi Engineers,
There is the need for me to access an existing structure against cracks when coring. Is there any calculation I can do or any test to carry out to prove this?
Any help?

RE: Coring of existing structure

Let's start again.

You wish to ASSESS an existing structure for the likelihood of cracking prior to coring operations.

Is the above what you wish to do? If so, we are going to need more information, but let's get the question understood first.

RE: Coring of existing structure

Is the purpose of coring to determine non-conforming material or to determine why something has happened. You need to locate the rebar prior to coring. I know of no qualitative manner of determining coring location, generally visual and based on experience.

With respect to the first item results of coring tests are often inconclusive, subjective and contentious. A clear understanding of the objective is required and any remediation. This should be established prior to coring, with all parties in agreement. My personal experience with coring for this item has been dismal. Coring may not be the panacea.

With respect to the second item, coring is always an interesting endeavour. You need to core where the damage has occurred, but also in an area of reduced stress to prevent damage to the structure. It is often that the area examined is a region of high stress. This where experience is required.

Dik

RE: Coring of existing structure

(OP)
Yes Ingenuity/Dik, the question is;
I wish to ASSESS an existing structure for the likelihood of cracking prior to coring operations.
The purpose is to core the structure(manhole) to create hole for ducts.

Erasa

RE: Coring of existing structure

Precast manhole manufacturers often publish a guide to limits on coring their precast concrete structures. You might try looking up their guidelines to see where, and how close, you would be allowed to core for various openings in their products. This would give you a good starting point for your research and assessments.
Dave

Thaidavid

RE: Coring of existing structure

if you are just making a hole (I assume in reinforced concrete?) for a (small) duct to go through, than unless the structure is deteriorated or this is a very large hole, why would you expect any cracks? If this is a larger hole, than suggest you need to reinforce the hole after you cut it to prevent cracking.

RE: Coring of existing structure

...and select a low area of stress, and, locate any reinforcing. Check really carefully if the structure is per-stressed.

Dik

RE: Coring of existing structure

Usually we do this kind of operation prior to pouring concrete by embedding a pipe of the required diameter.

KARMA

RE: Coring of existing structure

It seems the question is unnecessary. If you are in a compression section of the concrete you might weaken some of the resistance to crushing, not cracking. If you are in the tension part, the concrete has no tensile stress contribution, so why worry about cracks? Normally reinforced concrete design does not depend on the ability to resist tension.

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


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close