Dynamic pile testing

Dynamic pile testing by James Fisher Strainstall offers a fast and cost-effective method of determining the performance of pile foundations.

Using the SIMBAT technique, testing includes a number of features that enable data validation, including the specially designed optical theodolite.

The prime advantage of dynamic load testing is the speed of testing and its low cost. Typically up to 10 piles can be tested per day with preliminary results available immediately.

Dynamic pile testing methodology

JF Strainstall has been offering dynamic pile testing using the SIMBAT technique for many years. The technique is a dynamic pile test that allows the prediction of static load settlement behaviour of bored, cast-in-place and pre-cast driven piles.

The method is based on the reproduction of waves in long elastic cylinders. When the pile top is struck with a falling weight, the pile section is deformed (enlarged) and this travels down the pile to the toe where it is reflected back up. In a free, un-damped pile the particle velocity of the return wave would be identical to the original wave.

When a pile is surrounded and restrained by soil, part of the wave is reflected back up at every external restraint. The remainder of the wave continues downwards, so that at any one time there are both upward and downward forces and velocities in the pile.

The SIMBAT technique is able to separate these upward and downward forces to calculate the dynamic soil reaction, by measuring the difference between the upward force in a free pile and the real upward force measured.

 JF Strainstall upgrading SIMBAT dynamic load testing capabilities

JF Strainstall's SIMBAT dynamic testing capabilities will be given a boost with the deployment of a new purpose-made 400Kg drop weight system.

The rig will be able to deliver a dynamic load of up to 600kN in suitable ground conditions. The system will be deployed from a van and comprise of a tracked unit with a self-contained system for lifting and dropping the weights under free-fall conditions. The tracked unit will be able to operate through doorways enabling tests to be carried out on restrictive access sites.

This system will reduce the degree of manual handling required by test operatives and increases the capacity of piles that can be dynamically tested from a van deployed team, complementing our existing trailer-mounted 1-tonne drop weight system.