Data Acquisition Technology in Deep Foundation Piling and Anchoring Load Tests

Deep foundation and anchor testing according to ASTM D1143 and ASTM D3689 can be a cumbersome task with the large testing components – load beams, wood dunnage, heavy hydraulic cylinders – and the inevitable entanglement of hydraulic hoses and pumps. This equipment is only to apply the load – you also need the necessary devices to measure the deflection of the pile or anchor and then record the data for evaluation once the testing is completed.

In the past, data recording was another cumbersome activity and required a group effort to accomplish. The ASTM testing specifications require that load be applied in increasing increments at minimum 4-minute time intervals while recording both the applied load and the displacement of the pile or anchor.

In order to accomplish this, multiple people were required:

• someone with a stopwatch,
• someone to maintain the load with a hydraulic pump,
• someone to record the load applied,
• and another to monitor the deflection at each indicator placed on the foundation member.

It is easy to see that one person cannot do all tasks simultaneously for each load interval, requiring there to be multiple individuals to handle the pump and read gauges at the end of each interval. This becomes more difficult when the pile or anchor is nearing its failure load and continuous creep mode, even with a full team.

At Chance Foundation Solutions, we have upgraded our data acquisition equipment through Motionics with their PileSense™ Wireless Load Deflection Test Kit to modernize our testing capabilities. This wireless test kit consists of a pressure transducer and up to 6 digital indicators that use Bluetooth® to connect the indicators to a tablet installed with their PileSense load test app. This wireless test kit and the app bring all the data to one place and automatically records readings from each device at the time interval you have set. This reduces the number of participants needed to conduct a compression or tension test and frees them to prepare the next testing setup or complete other work.

The user can see the pressure applied and the deflection of the pile or anchor continuously in real time. With hydraulic cylinder calibrations, the app can convert the displayed pressure (psi) into load applied (lbs/kg) allowing greater control over load increments. Once the test is completed, the results can be reviewed in a tabulated form or a graph that can be displayed on the tablet device. Further analysis is suggested and can be conducted by sending the data via email to a desktop or laptop computer in the form of an editable spreadsheet. 

This test kit has been a wonderful upgrade to the Chance engineering team’s capabilities providing an extra set of “eyes” during each compression or tension test we conduct – meaning only one person is needed to run the test! No more holding a stopwatch and telling your coworkers to “Read!” or “Mark!” at the end of each interval and asking “What did you say?”. No more deciphering questionable handwriting, and no more tedious entry of data from paper to a digital format. If you need more information about the Motionics PileSense™ Wireless Load Test Kit, please contact Chance Foundation Solutions.