Evaluating Thermal Integrity Profiling Defects and Rating Criteria-Paper

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The study evaluates whether temperature reductions measured by Thermal Integrity Profiling (TIP) can supplement existing drilled-shaft acceptance criteria, which rely on effective radius and concrete-cover estimates and may be unreliable when concrete-volume data are uncertain.<br /><br />Researchers tested three 4-foot-diameter, full-scale shafts containing manufactured defects of different sizes, shapes, and locations. They compared TIP temperature profiles with defect dimensions and thermal simulations, and incorporated results from other studies. Temperature response depended on defect size and position relative to the sensor wires.<br /><br />Results showed a general relationship between defect cross-sectional area and temperature reduction. Defects affecting about 6% or less of the shaft area typically produced average temperature reductions of no more than 2°F and local reductions of up to 5°F. Defects of more than 6% to less than 12% were associated with average reductions of 2–5°F and local reductions of 5–9°F. Reductions above 5°F across most wires, or local reductions above 9°F, are proposed as unacceptable indicators, even when existing radius and cover criteria are met. One 12-inch-cube defect was flagged by temperature data but passed the existing criteria, illustrating the potential value of the supplement.<br /><br />The proposed temperature thresholds are provisional. The research covered a limited range of shaft sizes, concrete mixes, and peak temperatures, and additional studies are needed to confirm how defect characteristics affect TIP readings. Temperature-based assessment may be especially useful when concrete-volume information is missing or questionable.

Keywords

thermal integrity profiling

drilled shaft

acceptance criteria

temperature reduction

defect detection

concrete defects

effective radius

concrete cover

shaft integrity

structural assessment