Evaluation of Thermal Integrity Profiling for Deep Foundations

Assessing the structural integrity of bridge foundations is critical to ensuring the safety of the traveling public. However, nondestructive methods currently used in practice to determine the quality of drilled shaft foundations are severely limited by their inability to provide full coverage of the foundation cross-section, particularly in the critically important region outside of the rebar cage. The goal of the project is to evaluate the accuracy of a new Thermal Integrity Profiling (TIP) technique for quality assurance of deep foundations. The TIP method utilizes infrared thermal probes lowered into access pipes, which are cast into the foundation to measure the heat of hydration of curing concrete. Previous studies demonstrated that the technique can detect loss of concrete cover outside the rebar cage, as well as internal flaws such as cracking or voids. However, the studies did not assess the accuracy of the technique for indicating the specific location and extent of flaws. The research project is a collaborative effort between Iowa State University (ISU) and the Iowa Department of Transportation to evaluate the accuracy of the TIP method. A full-scale test shaft will be constructed with voids at predetermined locations. Measurements of shaft integrity will be compared for the new TIP method and the cross-hole sonic logging (CSL) method, which is currently the most commonly used quality assurance tool for drilled shafts. The ability and accuracy of the two techniques to detect the specific locations, size, and general shape of the known shaft defects will then be assessed. It is anticipated that the thermal integrity profiling will provide cost savings to state Departments of Transportation as a more economical alternative to CSL testing, or as a screening tool to identify which shafts should be further analyzed by CSL specialists.

Language

• English

Project

• Status: Active
• Funding: $44341.00
• Contract Numbers:

  DTRT12-G-UTC07

  25-1121-0003-135

• Sponsor Organizations:

  Research and Innovative Technology Administration

  University Transportation Centers Program
  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Performing Organizations:

  Iowa Department of Transportation

  800 Lincoln Way
  Ames, IA  United States  50010

  Iowa State University, Ames

  Institute for Transportation Studies
  2711 S. Loop Drive, Suite 4700, Program for Sustainable Pavement Engineering and Research (PROSPER)
  Ames, IA  United States  50010-8864
• Principal Investigators:

  Ashlock, Jeramy

• Start Date: 20120701
• Expected Completion Date: 0
• Actual Completion Date: 20131231
• Source Data: RiP Project 32973

Subject/Index Terms

• TRT Terms: Bridge foundations; Cracking; Heat of hydration; Nondestructive tests; Pile foundations; Probes (Measuring devices); Quality assurance
• Uncontrolled Terms: Crosshole sonic logging; Structural integrity; Thermal integrity profiling
• Subject Areas: Bridges and other structures; Highways; Maintenance and Preservation; I30: Materials;

Filing Info

• Accession Number: 01481677
• Record Type: Research project
• Source Agency: Mid-Atlantic Universities Transportation Center
• Contract Numbers: DTRT12-G-UTC07, 25-1121-0003-135
• Files: UTC, RIP
• Created Date: May 21 2013 1:01AM