46 JULY 2024 WorldWide Drilling Resource® Drill Shaft Testing Into Long-Lasting Bridges Adapted from Information by University of Illinois Urbana-Champaign (UIUC) Construction of drill shafts is vital for building stable and secure bridge foundations, that’s why Illinois Center of Transportation (ICT) and Illinois Department of Transportation’s (IDOT) aim to optimize their use in a joint project, “R27-188: Evaluating the Accuracy and Use of Drilled Shaft Integrity Testing Methods in Illinois.” Timothy Stark, University of Illinois Urbana-Champaign Civil & Environmental Engineering Excellence Faculty Scholar, and Abdolreza Osouli, Southern Illinois University Edwardsville associate professor, lead the project with Michael Short, IDOT District 3 program development engineer. The team was joined by UIUC doctoral candidate Abedalqader Idries, and they assessed the integrity testing methods for drilled shafts, which consist of a circular hole and filling it with concrete. “The project was developed to quickly and cost effectively test the foundation element of major bridge structures,” Stark said. “Drilled shafts support bridge piers, so if one of those piers do not meet capacity, you have a major problem.” Concrete foundation construction can be difficult to locate due to them being underground or underwater. Nondestructive test of drilled shaft concrete provides reliable assurance. “A lot of times, drilled shafts in small bridges might be 10 or 15 feet deep, but on a larger bridge they may be 50, 60, 80, even 100 feet deep,” Short said. “So, they’re really tricky to build, and they’re really difficult for an inspector to actually inspect and see what’s going on while they’re being built.” Two tests are involved; sonic logging, which uses steel tubes to measure vibration wave speed, and thermal integrity profiling, which continuously measures temperature during concrete curing and can be monitored remotely. The researcher constructed three full-sized test drilled shafts with intentional defects in Illinois, which were then tested by consultant experts to identify any defects. The test shaft enabled researchers to assess the performance of various test methods in detecting defects and establish integrity testing protocols for IDOT. The two methods have different strengths and weaknesses, with crosshole sonic logging more suitable for end-bearing shafts and thermal integrity profile better for shafts that rely on side resistance. Based on their research, Stark, Osouli, and Idries created a simple decision flowchart to help IDOT in selecting the most suitable drilled shaft testing method. Updates to IDOT’s drilled shaft specifications in the inspector’s checklist will enhance the effectiveness of integrity testing methods. “I like working with IDOT and ICT projects because the whole goal is implementation,” Stark said. “The research is being used. It’s in practice. That’s what I like to do: do the research and then see it implemented.” Integrity testing is crucial for building long-lasting bridges that perform well. “Integrity testing is one part of a good inspection process,” Short said. “It’s a good tool, but it is not a replacement for a good, experienced inspector to be present and paying attention to what’s going on during the construction process.” C&G WorldWide has the very best editorial of any drilling magazine as attested to by thousands upon thousands of readers WorldWide. Why? The variety of subjects covered - from the earth to the universe. WorldWide is Number One in the Drilling Industry for Solid Gold Service ~ with a Smile!™ What do you want to read about next? ronnie@worldwidedrillingresource.com
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