The Thermal Integrity Profiler (TIP) uses the heat generated by curing cement to assess the quality of drilled shafts and of bored, augered cast in place, continuous flight auger or drilled displacement piles. It may also be used for quality control and shape evaluation of jet grouting, slurry walls, and diaphragm walls. TIP evaluates the entire cross-section and the entire length of the foundation. Results are available shortly after shaft installation is concluded: TIP reveals necks or inclusions (regions that are colder than average), bulges (regions that are warmer than average), variations in concrete cover, and the shape of the shaft and cage alignment.
The average temperature within a concrete shaft is dependent on its diameter, the concrete mix design and on the time of measurement relative to concrete casting. Measured temperatures at the reinforcement cage vary with the distance to the center of the shaft and with the concrete cover.
The TIP starter system includes the TIP Main Unit and 12 Thermal Acquisition Ports (TAPs), along with the TIP Reporter Software. THERMAL WIRE® cables (smart sensing cables fitted with uniformly spaced digital temperature sensors) are ordered separately depending on the length and quantity needed. The cables are tied to the rebar cage and cast into the shaft.
Data collected by the TIP system is downloaded to a computer for analysis by the TIP Reporter Software. The TIP Reporter Software displays measured temperatures versus depth and mapped on cross sections of the shaft to provide profiling data. The Thermal Integrity Profile software helps identify areas of concern such as potential over-pour bulges, necking, or cage alignment irregularities. TIP Reporter also estimates the concrete cover along the entire length of the shaft. In addition to TIP temperature measurements, this analysis requires the total concrete volume as an additional input. The estimated effective shaft radius, reinforcement cage location and the concrete cover of the reinforcement bars can then be determined.
The Thermal Profiling Method was developed at the University of South Florida and originally implemented by Foundation and Geotechnical Engineering LLC (FGE). Research and development are a joint effort of FGE and PDI. The TIP conforms to ASTM Standard D7949 – Standard Test Methods for Thermal Integrity Profiling of Concrete Deep Foundations.
1Cotton, D., Ference, M., Piscsalko, G., and Rausche, F., (2010) “Pile Sensing Device and Method of Making and Using the Same” US Patent 8,382,369.
2Mullins, A. G. and Kranc, S. C., (2004), “Method for Testing the Integrity of Concrete Shafts,” US Patent 6,783,273.