Thermal Integrity Profiling (TIP)
Assessing Pile Integrity with Thermal Integrity Profiling
Thermal Integrity Profiling (TIP™) is a technology that utilizes the heat generated by curing of concrete to assess the integrity and quality of drilled shafts, augered cast in place (ACIP), micropiles and other concrete foundations. From the test results, necks, bulges, the as-built shape of the shaft, and variations in concrete cover and including steel cage eccentricities, can be characterized.
Drilled shafts and piles are prepared for Thermal Integrity Profiling during their construction, by attaching Thermal Wire® Cables to the reinforcing cage or center bar. When shafts are equipped with Thermal Wire cables, temperatures are automatically sampled throughout the concrete hydration process starting immediately after casting. GRL Engineers typically use a Thermal Aggregator (TAG) and TAP-Edge data logger to collect and review the TIP™ data in real-time via the Cloud.
These results may be evaluated for shaft shape and integrity, concrete cover, concrete quality, and for location of the reinforcing cage. The overall average temperature for all Thermal Wire cable readings over the embedded depths can be directly related to the total volume of concrete installed, and hence the average radius. Shaft integrity is assessed based on the average temperature measurements from each Thermal Wire cable at each depth increment. If the measured average temperature versus depth is consistent, the shaft is considered to be uniform in shape and quality. Bulges can be identified as localized increases in average temperature, while insufficient concrete quality or cross section reductions can be identified as localized decreases in average temperature. Anomalies present over more than ten percent of the effective cross-sectional area are normally seen in multiple Thermal Wire cables at the same depth. Because soil and/or slurry pockets produce no heat, areas of soil intrusion or inclusion are indicated by lower local temperatures.
Thermal Integrity Profiling is standardized by ASTM D7949 – Standard Test Methods for Thermal Integrity Profiling of Concrete Deep Foundations.