At 30 years old, I am assumming you have tried to locate the drawings with the client, building department, original engineer and/or original architect?

Column reinforcing, as long as it is not too conjested, can be located using a covermeter by someone with experience. Architectural finishes will have to be removed. Some of the more expensive covermeters can also determine bar size as well as depth. Vertical bars and ties would have to be located. Some destructive testing is recommended to confirm the covermeter results on a random sampling basis.

Xray can be used but it can be expensive and there still needs to be some destructive testing as cover depth cannot easily be determined by Xray, and could be limited by column size.

Determing info about the foundations, without drawings, is very likely going to require test pits, i.e. destructive testing.

 

Are they concrete columns??  Then maybe an X-ray or other type of testing could be done.  Or just check the columns as if they had minimal reinforcement.

For the footing - drill some holes in the basement floor and find out how big the footing is.

If the building is over 50 years old - BE CAREFUL.. I have found many problems with these older buildings - esp the ones built right after WWII