What is GNSS positioning and how accurate can it get?
GNSS stands for Global Navigation Satellite Systems. The most famous constellation is GPS, but nowadays it is possible to receive simultaneously...
GNSS stands for Global Navigation Satellite Systems. The most famous constellation is GPS, but nowadays it is possible to receive simultaneously the signal from multiple constellations, such as Glonass, Galileo, and BeiDou. This brings the numbers of satellites visible in the sky close to 100, which results in higher chances of getting a 3D position even in non-open sky conditions. A professional-grade GNSS system is also able to process differential corrections, which are normally broadcasted from a server. This is a real-time computation that results in a corrected position as accurate as a few centimeters.
How close to the surface is it possible to measure with ultrasonic pulse-echo technology?
While this is being improved all the time it is possible to give a reference for this. A major study was carried out in Germany that deals with...
While this is being improved all the time it is possible to give a reference for this. A major study was carried out in Germany that deals with this topic. Here it was shown that 16 mm rebars could be detected with a minimum cover of 20mm. The reference to the paper is shown below.
Detection of near-surface reinforcement in concrete components with ultrasound Sarah Vonk1,*, and Alexander Taffe1 1HTW Berlin – University of Applied Sciences Berlin, Nondestructive Testing in Civil Engineering Department, 12459 Berlin Link to paper
How deep can I measure with the Pundit PD8000?
There is no definitive answer to this question as it depends very much on the concrete quality and the amount of steel present. Using the Pundit...
There is no definitive answer to this question as it depends very much on the concrete quality and the amount of steel present. Using the Pundit PD8000 instrument with the Far Field macro selected (low frequency and high transmission voltage), depths of up to 2m have been achieved. However, it is also possible that depth penetration may be limited to about 1m if the concrete quality is not good, or if there is a lot of steel present in the structure.
What is GPR?
GPR is a compact device that scans the subsurface in a non-destructive way. It can penetrate the surface from a few cm down to tens or hundreds of...
GPR is a compact device that scans the subsurface in a non-destructive way. It can penetrate the surface from a few cm down to tens or hundreds of meters, based on soil conditions and antenna characteristics.
Is it possible to measure steel fibre reinforced concrete with ultrasonic pulse-echo?
Yes. Unlike electromagnetic methods such as those employed by GPR and cover meters, which do not work on steel fibre reinforced concrete,...
Yes. Unlike electromagnetic methods such as those employed by GPR and cover meters, which do not work on steel fibre reinforced concrete, ultrasonic pulse echo is well suited for measuring on this material. It has been successfully used for detecting voids, detecting cover depth to rebars and pipes and also for determining the thickness of shotcrete layers.