Reuse of Existing Foundation

[jteahan]

How does one assess the feasbility of reusing an existing foundation? We are involved in reconstruction of a manufacturing facility (several buildings each single story, approx. 12,000 SF) after an insured loss of the superstructure. Are there publications/articles written that would help us conclude whether we should abandon or reuse the substructure?

 

[ChrisMcLean]

This is an interesting query that I have come across as well - sometimes removing the existing foundations will cause more problem then leaving them in-situ.

We tend to approach the problem based on the information available relating to the existing structure and the specific foundation design eg. engineers designs, SI data, on-site inspections reports and as-built design logs. It's clear that in this case of course you would have to consider the mechanism by which the superstructure was destroyed (which you don't mention but sounds like fire) and the possible effects that could have on the foundations.

I would be really interested to hear how the many (far more learned than I) posters to this forum would deal approach this situation.

 

[ishvaaag]

Except that all indicates the foundation is competent enough and for sure, I would likely resort to some kind of piles for the new foundation in order to minimize the works to be made, specially if such kind of piles is available at reasonable cost. If not, my first concern would be to minimize disturbance to what existent, in the intelligence that it is a case of not being necessary its complete removal.

 

[Focht3]

[blue]ChrisMcLean[/blue] got it right - you have to weigh the available information before making a decision. Generally speaking, I'll only go along with re-use if the new structure is a duplicate of the original. I don't like new loading configurations on old footings -



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

 

[Qshake]

Most of the applications that I've seen, the old foundation is cut-out to a certain depth below grade and the new work is situated around it if possible. I have seen a few footing and pile extractions. Overall complete removal is not bad, but may be avoided.

I am not a proponent of reusing foundations for the reasons already mentioned and the fact that NDT is out of the question due to expense. Or stated another way, you'll spend more in investigative engineering than in replacement materials for the new foundation.