×
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

Determine Existing Foundation

Determine Existing Foundation

Determine Existing Foundation

(OP)
A coworker brought up this problem and I thought it would make a worthy topic of discussion on the forum.  

An existing warehouse is to be retro-fitted to house power generating equipment.  The records of the existing foundation are scanty and contradicting, some say piles and some say spread footings.

How can the existing foundation type be determined with minimal disturbance?  GPR comes to mind as does manual electro-magnetic mapping.  Any other ideas/suggestions?  Can siesmic data be used in this manner?

Thanks and    

RE: Determine Existing Foundation

I have used impact echo methods to define the extent and details of the concrete.  That's just the first step though.  You also have to figure something about the rebar size and placement.

Steve Braune
Tank Industry Consultants
www.tankindustry.com

RE: Determine Existing Foundation

Power generating equipment (turbines, transformers, etc.) generates a fair amount of dynamic loads; this isn't a simple retrofit.  The new equipment needs to be isolated from the existing structure, and the existing foundation needs to be carefully evaluated for risk of damage from steady state - and variable - dynamic loading.  (Don't forget about start-up and shut-down loadings.)

You will need a detailed geotechnical analysis, too - with cross-hole testing near the major equipment.  This will probably run 3 to 5 times the cost of a typical geotechnical study for a "simple" warehouse.

This work will take at least twice as long - and likely cost more than twice as much - as designing a new building to contain the same equipment...



Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora.

RE: Determine Existing Foundation

Why not dig a test pit to observe the existing foundation?

RE: Determine Existing Foundation

Electrical resistivity could be helpful. Perhaps you will not obtain the dimensions of the elements but it could tell you if there is a spread footing or a pile below your columns. Nevertheless, Focht3 is right about the necessity of a widen geotechnical investigation.

RE: Determine Existing Foundation

Considering the phenomenal underground duct requirements, interference issues, high area loads, dynamic harmonic compatability concerns, it would seem doubtful to save money retrofitting an existing foundation.

RE: Determine Existing Foundation

Interesting quandry.  You are probably trying to avoid digging around the base, in case it turns out to be ground-supported.  If I were you I might just go ahead with a geotechnical investigation and see for yourself how they should  have done it.  Would you have built on spread footings or piles?  What is the depth to bearing, would piling even be feasible?  A geotechnical report around and inside the building I think would be of great help, though I agree with Focht3, if you are building to accomidate vibration, you may need to go w/ a more solid design anyway.  Best of luck.  Keep us posted.     

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