Specifications include, but are not limited to: Crosshole Sonic Logging (CSL) is a downhole test method for evaluating the quality of concrete in drilled shaft foundations. Polyvinyl chloride (PVC), or steel access tubes, are cast-in-place in the concrete shaft during construction. The CSL test is conducted by sending a sonic pulse wave through the concrete from a sonic emitter in one water-filled tube to a receiver in a second water-filled tube. Using the distance and the measured travel time between the tube pair, the speed of the pulse wave traveling through the concrete can be determined. The speed can then be correlated with quality of concrete. CSL testing is performed by lowering probes into two tubes and the source emits a pulse, while the receiver response and probe depth are simultaneously recorded. Data recorded by the receiver are then processed by a computer-based data logging system. The concrete integrity is evaluated by analyzing the wave travel times and wave velocities. Longer travel times and corresponding slower velocities suggest irregularities in the concrete between the tubes, provided good bonding is present between the tubes and concrete interface. A complete loss of signal is indicative of a signal defect in the concrete between one or more tube pair combinations
