Pile Driving Analyzer® (PDA)

High strain dynamic testing is conducted on installed driven and cast-in-place piles using a Pile Driving Analyzer® (PDA) system.  PDA testing combined with CAPWAP® analysis provides an estimated pile capacity, including the resistance distribution along the pile shaft and the base resistance.  Additional measurements made by the PDA include the energy delivered to the pile from the pile hammer or drop weight, the compressive and tension forces in the pile during testing and the integrity of the pile.

Pile Integrity Tester (PIT)

Non-destructive low strain dynamic testing is conducted on concrete and timber piles using a Pile Integrity Tester (PIT).  The PIT uses the sonic echo (or pulse echo) method to identify significant defects in the test pile, such as cracks, necking, soil inclusions and voids.  The PIT can also be used to determine the length of piles.  The PIT captures, displays and stores the test data for further software analysis.

Thermal Integrity Profiling (TIP)

Thermal Integrity Profiling (TIP) is a relatively new test method for assessing the integrity of cast-in-place concrete footings, such as bored piles, CFA piles and micro-piles.  The test works by measuring the temperature of the concrete as it cures and hydration occurs.  Cold regions may indicate an integrity issue (e.g. necking, inclusion, poor quality concrete), and hot regions may indicate a bulge in the pile profile.  Measurement intervals can be programmed, but are typically set at 15 minute intervals.  The temperature of the concrete is measured by sacrificial thermal wires, which are attached the the longitudinal reinforcing bars within the pile and have individual temperature sensors every 300 mm, or so.  The test is typically complete between 4 hours and 72 hours after the concrete is poured, depending on pile diameter.  There are many advantages of TIP including:

  • fast assessment of pile integrity (reduced construction time, potential problematic piles can be dealt with faster);
  • estimating the shape of the pile;
  • assesssment of concrete outside reinforcing cage;
  • easier installation of testing equipment (thermal wires are much easier and less obtrusive compared to CSL access tubes);
  • assessment of pile integrity is not limited by pile length or high-resistance founding material;
  • high confidence locating areas of concern;
  • determination of concrete cover and eccentricity of the reinforcing cage.

Static load tests

Black Geotechnical can conduct axial (compression and tension) and lateral static load testing to determine pile performance under specified loads.  If the loading is high enough and within the safe structural capacity of the pile, the ultimate geotechnical resistance of the pile can be determined.  Calibrated digital sensors including load cells, strain gauges and displacement transducers, are used to continuously display and record the load-deflection behaviour of the pile.