BTP Magazine # 252 - December 2011

Sensors to measure the deflection of the piles (p.88).


Specialists of continuous flight auger piles or Kelly piles know it for a fact : the verticality of the structures must sometimes be carefully controlled while achieving secant piles or certain type of isolated piles. To make this possible, Jean Lutz has developed two new systems of measurement : the Prad and the Taupe.

The sensor Prad fits both the auger and the Kelly, down the tools. It measures the deviation and the bottom pressure : on each rise of the drill, the Prad transmits the data through radio to an interface of calculation and display, installed in the cabin of the machine - typically the Jean Lutz SA interface named Dialog. This instrumentation can also handle the data transfers to the offices of site supervision, receive instructions or operating procedures, and issue customizable reports.

In the case of Kelly piles, the Prad provides measures issued at the end of each rise, therefore almost in real time. For continuous auger piles, the data transfer only occurs once the pile is completed, after drilling and concreting. The operator then has all the information that will enable him to better reposition the next pile, regarding the possible deviation of the pile just finished. It can also adjust the amount of concrete to be injected.

The Taupe sensor, made specifically for augers, measures and transmits in real time all the information of deviation and concrete pressure, making possible the adjustments needed regarding the drilling and the concreting. During the implementation of the pile, the data transmission between the bottom and the head of the auger is provided by a single strand conductor wire, which will be set up all along the auger.

The Prad and the Taupe sensors use technologies based on accelerometers and gyroscopes.