Abstract:
The design for the construction of 3 additional downstream monoliths at the Kentucky Lock in Grand Rivers, KY, included a total of 21, 5’ diameter drilled shafts. The project specifications included tolerances for the drilled shaft verticality as well as the debris thickness allowed at the base of the shaft prior to concrete placement. The project location and variable installation schedule made it very difficult to have a testing engineer onsite to perform the testing. Remote data collection was proposed and accepted. For each shaft, data regarding the shaft geometry and verticality, along with the measurement of the debris thickness at the shaft base, were collected remotely, in real time. Reports were then submitted for approval shortly after the testing was completed. Schedule changes, intermediate tests, and repeat testing were easily accommodated due to the flexibility of remote data collection.
The drilled shaft design also included a large beam to be installed within the rebar cage, with varying depths for each shaft. Cross-Hole Sonic Logging (CSL) was specified to evaluate shaft integrity. Eight access tubes were installed on the rebar cage in a pattern to allow line of sight around the steel beam. Additionally, 4 access tubes were placed near the center of the shaft on the beam to allow CSL profiles to evaluate integrity to the interior of the shaft. Presenting the CSL results of this irregular access tube pattern was a challenge that was ultimately resolved with the help of a customized report structure developed by the testing engineers.
This case study will focus on the successes of remote data collection as well as the performance of CSL and presentation of the results in conditions which were challenging to the test method.