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

New opening in exiting wall

New opening in exiting wall

New opening in exiting wall

Hi, I move this thread to the structural forum (it was in the demolition forum) since I think that people looks more at this forum....

We are doing a preliminary study for addition an opening in a wall for an existing tank. The existing wall is very thick (2 m thick) concrete wall. The tank is about 5 m height and we are planning to do the opening at the bottom of the wall (the bottom of the opening is close to the bottom of the tank). The opening is about 2 m by 2 m to allow for an inspection pit/box for pipes. Any references or input about the considerations for analysis/design/construction of this new opening will be appreciated.

RE: New opening in exiting wall

We have a demolition forum? (Sarcasm)

I'd say the biggest issue is ensuring the remaining structure has sufficient strength. At 2m thick (wow) it likely does and is also likely able to easily support you cutting holes in it.

I presume you have the original reinforcement drawings for the tank? My first step would be to analyze the tank with the proposed 2m x 2m opening. For myself I'd use a simple FEA model in RISA but you could reasonably do this via simpler calcs assuming the meter or so of concrete above the opening is taking not only it's unit tributary width of load but also is now supporting the loads of the 2m of tank wall you removed. You'll also have high corner forces on the opening but at 2m thick I doubt corner cracking is a big concern.

For the demo (if that's in your scope) I'd recommend sawcutting your finished opening size on each side (likely cutting the reinforcement in this step) and then using drills or pneumatic chisel tools to roughly demo through the opening. The interior of the opening can then be cleaned up with pneumatic tools to be flush with the saw cut sections. Some consideration to corrosion protection of the exposed, cut rebar is in order.

I assume once your opening is cut you're filling it with pipes and other stuff but will need to fill the annular space with something to make the tank waterproof again. Probably just a butyl rubber seal around the pipes and such and then fill the space with grout, but depending on things you may need something more robust or leak proof.

Ian Riley, PE, SE
Professional Engineer (ME, NH, VT, CT, MA, FL) Structural Engineer (IL, HI)

RE: New opening in exiting wall

Hi TME, thanks for your reply. So basically, your suggestion is to check the stresses in the vicinity of the opening based on the new wall configuration with new opening. I think that in our case, DL are more critical than the LL. Also, could you expand about this statement "...but also is now supporting the loads of the 2m of tank wall you removed.". Thanks again !

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! Already a Member? Login


White Paper - Reliability Verification for AI and ML Processors
Artificial intelligence and machine learning are seeing growing adoption in a wide range of applications. ICs used for AI/ML applications are characterized by large parallel processing computation units, high power dissipation, and complex circuitry that can deliver maximum performance within a strict power budget. Download Now

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