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Cross Hole Sonic Testing Service
In CHAMP test ,two Ultrasonic probes one a Transmitter and the other a Receiver are lowered and lifted usually in unison in their respective water –filled parallel access duct(s) about 40 mm Internal diameter , lowered along with the rebar cage and cast into the concrete during construction of piles) through suitable cables and depth measuring digital rotary encoders to test the full shaft length from top of bottom .The transmitter probe generates ultrasonic pulses at frequent and regular intervals during the probes ‘ controlled travel rate cross the concrete and eventually reaches the receiver. The transducers were lowered into the water filled tube , until the lower bottom. In this particular case Single Hole Ultrasonic Logging (SHUT) were performed The test was performed while pulling both transducers together (with probe separation of 700 mm) upwards in preinstalled water filled 40 mm PVC access duct. The CHAMP instruments & CHA software then plots the travel time between the tubes versus the depth .As long as the time is fairly constant, it shows that there is no change in concrete quality. A sudden increase in arrival time and or a sharp decrease in energy indicate a defect at this depth. Thus the ultrasonic logging profile is produced by CHAMP and saved for later interpretation.