Results of the CSL shall be presented in a written report within (5) working days of completion of The report shall include presentation of CSL logs for all tested tube pairs including:
Presentation of the traditional nested signal peak (e.g. “waterfall”) diagram as a function of time plotted versus depth.
Computed pulse first arrival time (FAT) or pulse wave speed versus
Computed relative pulse energy or amplitude versus
A CSL log shall be presented for each tube pair. The rating of the shaft integrity considers the increases in “first arrival time” (FAT) and the energy reduction relative to the arrival time or energy in a nearby zone of good concrete.
Flaw or Defect zones, if any, shall be indicated on the logs, listed in a table, and their horizontal and vertical extent and location discussed in the report text. Flaws must be addressed if they affect more than 50% of the profiles. Defects must be addressed if they affect more than one profile (a profile is the result of complete investigation from bottom to top between two tubes) at the same cross section. Flaws or Defects covering the entire cross section define a full layer concern requiring repair. “Addressing” a Flaw or Defect means as a minimum an evaluation by tomography if the concern is localized (e.g. not across the full section), and/or, depending on the depth to the concern, additional measures like core drilling, repair or replacement, repeat tests after a longer waiting time or testing by other methods (gamma-gamma, low strain, high strain).
(Note: A FAT increase corresponds to a wave speed reduction. Concrete strength can be related to the wave speed. Because the tubes might not be perfectly straight or even parallel, a fixed absolute limit of a wave speed value cannot be used for evaluation for perimeter profiles. Wave speed is best determined from the test results from the major diagonals. It should also be noted that if the referenced good concrete exceeds the specifications, then a concrete with a local 20% wave speed reduction might still exceed the specifications. If the test is of young concrete and the average wave speed across the major diagonals is less than 3,000 m/s (10,000 ft/sec), consideration should be given to repeating the test after a longer wait to assure the concrete has good strength.)
The log for each pair of tubes shall be clearly identified and oriented relative to the structure. The Engineer shall have (5) working days to evaluate the results and determine whether the drilled shaft construction is acceptable or not. CPB shall not perform any load testing or other construction associated with these drilled shafts until after acceptance by the Engineer. If the drilled shaft is accepted by the Engineer, the Contractor may then proceed with construction. If the Engineer determines the drilled shaft is not acceptable, the drilled shaft shall be cored, repaired or replaced by the contractor at the Ccontractors expense and with no increase in contract time.