Drilled Foundation Testing, a comparison of different QA/QC testing Methods-PPT Presentation

PPT Presentation

Pdf Summary

The presentation compares non-destructive quality assurance methods for drilled foundations: Crosshole Sonic Logging (CSL), Thermal Integrity Profiling (TIP), Gamma-Gamma Logging (GGL), and shape/verticality testing.<br /><br />CSL sends stress waves between water-filled access tubes. Potential defects are indicated by reduced signal strength or delayed arrival times. TIP evaluates concrete integrity using heat generated during curing, relating measured temperatures to the volume of concrete placed; corrections are needed near the shaft’s top and bottom. Shape testing measures shaft profile and verticality, while GGL provides another integrity assessment.<br /><br />At Arizona’s Gilbert Road Bridge, TIP and shape-test diameter measurements agreed within 1–1.5 inches across 22 shafts. Using both methods helped locate potential problems and understand cage placement and design. However, CSL identified questionable zones not apparent in TIP or GGL results, raising questions about access-tube debonding and interpretation.<br /><br />A Tacoma bridge project provided a confirmed example of a defect. CSL indicated an anomaly around 7 feet deep, where the tremie pipe had been withdrawn during construction. Cores from two locations found approximately six inches of washed gravel, confirming the defect. TIP showed a temperature decrease at that depth across all wires, particularly near the time of half-peak temperature, but its calculated radius remained above the typical 6% threshold.<br /><br />The cases demonstrate that testing methods can produce different indications and that results should be interpreted together with construction records and, where needed, coring. The presentation recommends considering stricter TIP guidelines when temperature drops occur consistently across all thermal wires.

Keywords

crosshole sonic logging

thermal integrity profiling

gamma-gamma logging

drilled foundations

quality assurance

concrete integrity

shape testing

verticality testing

bridge foundations

construction defect detection