Thermal Integrity Profiling of Drilled Shafts-Article

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Thermal Integrity Profiling (TIP) is a non-destructive method for assessing the integrity and geometry of drilled shafts and other cast-in-place foundations. It uses the heat released as cement hydrates: a probe lowered through standard access tubes measures temperatures along the shaft, while thermal models predict the normal temperature pattern for the concrete mix, shaft dimensions, surrounding soil, and test time.<br /><br />Departures from the expected pattern can indicate defects. Regions with missing or reduced concrete, such as necks or inclusions, tend to be cooler; excess concrete, such as bulges, tends to be warmer. Measurements from multiple tubes can also help identify cage eccentricity, concrete cover, and shaft shape. The method can assess concrete both inside and outside the reinforcing cage, addressing areas that cross-hole sonic logging and gamma-gamma logging may not cover.<br /><br />Field examples and tests with deliberately introduced anomalies showed that temperature profiles can reveal changes in shaft geometry and detect concrete losses. Results can be interpreted qualitatively or compared with numerical models and construction records for more detailed assessment. TIP can also provide information about the concrete’s hydration process.<br /><br />TIP is complementary to existing integrity tests rather than a replacement for them. It depends on heat from curing concrete, so testing must occur while a useful temperature gradient remains—typically within 2–10 days, depending largely on shaft diameter. Model-based acceptance may also require accurate concrete-mixture information.

Keywords

Thermal Integrity Profiling

TIP

drilled shafts

non-destructive testing

cast-in-place foundations

concrete hydration

temperature profiles

shaft geometry

defects detection

thermal models