If major defects exist, the test estimates their magnitude and location; it may also determine pile length.It requires minimal pile preparation, and has been routinely used worldwide for many years.Because of its simplicity, speed of execution and low cost, it can be performed on 100 of the piles on a given job site.The impact of the hammer generates a compressive stress wave in the pile, and an accelerometer placed on top of the pile monitors the motion associated with this wave.
The stress wave propagates down the pile shaft, and is reflected when it encounters either the pile toe or a non-uniformity of the shaft. These reflections cause a change in the acceleration signal measured on the pile top, which is picked up and processed by the Pile Integrity Tester (PIT) by Pile Dynamics and interpreted by an experienced SLP engineer. It assures the absence of cracks and voids and verifies concrete quality on elements built with inspection tubes. Low Strain Integrity Pile Test Full Length OfThese tubes are usually attached to the reinforcement cage along the full length of the shafts. After concrete has been poured, the tubes are filled with water. Starting at the bottom of the shaft, a transmitter emits an ultrasonic signal in one tube. The signal is sensed some time later by the receiver in another tube. The sensors (transmitter and receiver) are than moved some distance upward along the shaft and the process repeated until the entire shaft length is scanned. The engineer repeats the test for each pair of tubes, allowing for the investigation of defects both along the length and by quadrant. From the test results, necks, bulges, variations in concrete cover and the as-built shape of the shaft, including steel cage eccentricities, can be characterized. Drilled shafts and ACIP piles are prepared for Thermal Integrity Profiling during their construction, by the installation of Thermal Wire brand cables or access tubes. We perform this test using a Thermal Integrity Profiler (TIP) by Pile Dynamics. When shafts are equipped with Thermal Wire cables, temperatures are automatically sampled throughout the concrete hydration process starting immediately after casting. We typically retrieve the data for analysis and reporting after 12 to 48 hours depending upon shaft diameter and mix design.
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