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Technical Service Center
Materials Engineering and Research Lab

Current Testing Procedures for Large Anchor Bolts

Current evaluation methods consist of "lift off" tests, where a jack is used to pull the end of the bolt and measure the amount of movement. This is a destructive test, inducing loss of bond between the bolt and the surrounding concrete.

Research Consortium to Find Nondestructive Testing Procedures

To find ways to test large anchor bolts without destroying them in the testing, Reclamation formed a research consortium under the auspices of the American Concrete Institute's Strategic Development Council, to investigate nondestructive testing (NDT) methods for determining the in-place load-carrying capacity of large anchor bolts cast in concrete. This consortium consists of partners interested in evaluating various NDT methods for solving this serious and imminent problem. Each partner provides its own funding to support the consortium.

The goal of the consortium is to find a nondestructive testing procedure that can determine the load carrying capacity of large anchor bolts. This procedure should be able to accomplish this while only accessing one end of the bolt, and should be capable of measuring a 10% loss in cross-sectional area within the bolt.

The NDT of Large Anchor Bolts Research Consortium believes that the best method for resolving this problem is for the members of the industry to work together to find a solution to this problem. It is unlikely that any single organization has the resources or funding to develop a suitable NDT procedure on their own. It is proposed that the interested parties work together, each organization taking a bite of the apple, working with the consortia to ensure that we are not duplicating efforts.

Currently, the Consortium is reviewing testing procedures proposed by:

The Consortium will promote research in this area by uniting industry partners that are willing to fund work with experienced researchers capable of advancing the state of the art. We believe that it will be possible to combine funding from various sources. The Consortium will continue its efforts bringing attention to this problem so that all interested participants are working together.

In addition, the Research Consortia will be forming a Second Party Evaluation Program that will provide researchers and funding agencies with an objective evaluation of NDT methods for large anchor bolts.

The first step of this program will be to determine the most likely failure modes, based on historical evidence, and structural analysis. Using this information, we will design and build a testing program that will provide researchers with problems similar to those found in the field, and provide enough information that probability of detection curves can be developed.