Deep Foundation Integrity Testing

CROSS-HOLE SONIC LOGGING (ASTM D6760)

Twining experts provide structural integrity evaluation for drilled shafts / CIDH piles. CSL (Cross-hole Sonic Logging) integrity testing is standardized by ASTM D6760 – Standard Test Method for Integrity Testing of Concrete Deep Foundations by Ultrasonic Cross-hole Testing. CSL is one of the most common Nondestructive test methods for Deep Foundation Testing.

Benefit of CSL Testing

  • Evaluates integrity and relative concrete quality and consistency of drilled shafts and other cast-in-place concrete structures.
  • Identifies location of potential shaft anomalies
  • Performs real-time analysis on site, as well as data transfer with CHA-W reporting software for additional analysis.

Twining professionals can provide comprehensive engineering analysis by means of the Cross-hole Sonic Logging in order to assist owners and contractor to determine the quality and consistency of the concrete of drilled shafts, CIDH Piles, Slurry Walls, and other types of deep concrete foundations.

Deep foundations are prepared for integrity testing by CSL during their construction by installation of at least three tubes with a minimum inside diameter of 38mm (1.5 inches). These tubes are usually attached to the reinforcement cage along the full length of the shafts. After concrete has been poured, the tubes are filled with water. In CSL, a transmitter emits an ultrasonic signal in one tube and the signal is sensed sometime later by the receiver in another tube. Poor concrete between the tubes will delay or disrupt the signal. We use the state-of-the-art equipment, PDI’s CHAMP-Q analyzer which meets or exceeds the specifications of ASTM D6760 and several other cross-hole sonic logging codes and standards. The testing engineer lower the transmitter and receiver into the bottom of the shaft and moves both the probes upward in unison, until the entire shaft length is scanned. This is being reaped for each pair of tubes. Engineers can interpret data in the field for delayed pulse arrivals (or low signal strength) which in turn indicate potential defects. Results are presented in a detailed and illustrated report.