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RE: Testing for Anchor Bolt Embedment

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I think that the vertical reinforcement in the concrete will create confusion and lead to erroneous conclusion.


 Ron Hill <ronhill(--nospam--at)> wrote:

I am familiar with this UT technique. 


You will need a UT machine with a crt (oscilloscope) screen and not the digital read out.  A good technician will be able to interrupt the screen.  The transducer will need to be a low frequency type if the bolts are extremely long.  The size of the transducer will need to be smaller than the bolt diameter to avoid the threaded area.


You should have a test bolt of the same size and material and threads for the tech to practice with.  Test each bolt and decide the embedment length.  You will get some strange answers on some of the bolts but this may be due to flaws in the material. 


If the end of the bolt is threaded, you may get fuzzy lengths depending on how the tech determines the length to the first thread or end of rod.  If the rod is bent in an ?L? or ?J? hook, you may not get a good reading.





Ronald A. Hill, P.E.

HILL Consulting Engineering

PO BOX 26525

Birmingham, Alabama 35260 USA

Phone: 205-823-4784

FAX: 205-823-4145

email: ronhill(--nospam--at)



-----Original Message-----
From: THunt(--nospam--at) [mailto:THunt(--nospam--at)]
Sent: Tuesday, December 10, 2002 4:09 PM
To: seaint(--nospam--at)
Subject: Testing for Anchor Bolt Embedment


I am reviewing the anchorage of a hospital emergency generator with 40 - 3/4 inch diameter cast-in-place anchor bolts but the drawings do not show the embedment depth.  Does anyone know of a field test to determine the embedment depth?  I am thinking there must be some type of sonic test that could measure the rebound and determine the bolt length.  Any ideas?

Thomas Hunt, S.E.
ABS Consulting

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