The latest Sonic Logging system from Testconsult is the SC-XT2000. The system is designed for integrity testing large diameter concrete piles, diaphragm wall, barrettes etc, by the ultrasonic cross hole method. The equipment is purpose designed and includes a sophisticated 2D and 3D tomography module. The equipment and software provides the following advantages:
- Fast and easy to use on site
- One man operation
- Robust, reliable equipment
- Accurate data collection
- Rapid email report facility
- Full data viewing and tomography software
Sonic Logging is a cross-hole test whereby ultra sonic transducers are used to measure the transit time of sound in concrete. The test is carried out in foundations where steel tubes have been installed during construction, normally to the full depth.
An electronic winch operates the system and triggers a signal between tubes at 2cm intervals over the length of the piles. The signal, which is about 50 - 60KHz, is captured and stored as a time/amplitude trace and each trace consists of a time lag followed by the received signal, the time lag representing the time taken for the signal to travel from the emitter to the receiver.
Impulse signals are modulated to produce a waterfall plot for each profile measured. The operator can choose to display the first arrival time (FAT) and signal energy simultaneously if needed. The first arrival time can be used to determine the ultrasonic pulse velocity (V), if the distance between tubes is measured. V is related to concrete properties using the following formula V2 = E/p (1 - µ)/(1 + µ)x(1 - 2µ) Where E is dynamic modulus of concrete, p is density of concrete and µ is poissons ratio.
On site, sonic profiles are generated automatically, without needing to return to the computer between pairs of tubes. The computer automatically levels profiles with respect to either the top the tubes or an absolute reference level, if entered. Pile cut-off level can also be displayed on profiles if required.
Hardware
The Heart of the system is the hand luggage sized, rugged site computer, contained in a waterproof case, with full stainless steel keypad. It is powered by a 72AH Ni-MH battery, which enables several hours site use. It can also operate using the supplied 100-240VAC power adapter/charger or 12VDC car power lead. A USB interface is fitted for peripherals and a portable CDRW is included with the system. The electronic winch unit is constructed from high grade stainless steel and logging operations can be controlled and monitored from it.
Software
The SCAP analysis and reporting software is windows based and user friendly. It is able to output results in the following formats:
- Waterfall Plot
- First Arrival Time (FAT) – auto or manual
- Signal Energy – relative changes in dB
- 2D tomography at selected levels
- 3D tomography over selected lengths
- ASCII output of FAT
- Single Impulse response
Details of pile diameter, cut-off level, toe level, tube top level and plumbed depths can be entered into the SCAP software for each test. Profile displays are automatically adjusted to ensure that levels are consistent. Details of tube orientation can also be recorded together with the operator’s interpretation of results.
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