Determining depth of existing caisson

[ZTGR]

Hello all,
I need some help on where i can find a method or guide on how to determin the depth of an existing caisson without having to drill, sonic test or some alternatives?? any info is appreciated.

 

[JAE]

Why do you need to know the depth? Load capacity? if so, some type of load test might suffice.

 

[Focht3]

Your best bet is to find someone to "ping" it for you; my preference is Larry Olson's group out of Denver. Check out the following link which discusses a number of techniques that could be used:

http://www.fhwa.dot.gov/bridge/gt-16.pdf

Larry's company web site can be found at:

http://www.olsonengineering.com/aboutus2.html

Disclaimer: Larry was a classmate of mine in grad school, and a good friend.

 

[ZTGR]

Focht3 thnak you, your reply was helpful.

 

[scofie]

I recently had this type of work done also. I needed the depth of three existing drilled shafts for a telecom tower because the original foundation design drawings could not be found. Being in Florida, I used a company called GRL with offices in Orlano to do impact testing with a Pile Integrity Tester (PIT). The test costs about $1500-$2000 and works well to get a signature of the depth of the shaft non-destructively. Basically, a little hammer is used to tap the top of the shaft and the sound wave return time is monitored.