Testing foundations on a project isn’t mandatory in all locations but that doesn’t mean it should be overlooked. So even if your project has included PDM before, find out more about what Pile Driving Monitoring is, what it entails and the benefits it can bring to any project.
What is Pile Driving Monitoring?
Pile Driving Monitoring (PDM) is a method used to confirm pile design assumptions, assess the pile axial capacity and assist in managing the risk of pile tip buckling. It is also used to ensure the structural integrity of the piles during driving and is the best way to achieve safe pile installation without causing delays.
Where can it be used?
PDM is widely used in both onshore and offshore construction and can be carried out above and underwater. Typically, it’s used during the installation of offshore wind farm foundations, jacket pile foundations and the construction of ports and harbours.
Although it can add value to any project, it’s especially important to projects where there is a risk of premature driving refusal or on a site where there are challenging geological conditions.
How do you carry out PDM?
Pile Driving Monitoring should be carried out by an expert team with a good understanding of the installation process in order to get the most accurate results, without causing delays. The process involves attaching strain gauges and accelerometers to the top of the pile. When the pile is struck by the hammer, it generates stress and velocity waves which travel along the pile and mobilise the shaft friction and the base pile capacity. This process generates reflected stress waves that travel back to the pile top and are recorded and analysed to calculate the actual hammer energy transferred to the pile as well as the pile ultimate bearing capacity and the soil resistance under continuous driving conditions or in long term.
The benefits of including PDM in your project
Although it can be easy to overlook PDM until there is an issue, by planning it into a project from the beginning, PDM can bring several benefits, without lengthening the installation process.
- PDM provides real time quality control for installation operations as it’s the only way to evaluate the stresses induced anywhere in the pile during driving.
- The results can be used to confirm the static axial pile capacity which is especially important where there is a risk of premature driving refusal or of encountering challenging geological conditions
- Assumptions made during the pile design (axial ultimate capacity, predicted behaviour during installation) can be validated using the PDM results. In some cases, this can result in cost savings in terms of pile dimensions and associated installation timescales.
- When carried out with the Pile Dynamic Test it is considered as a valid means to avoid expensive pile static load tests, particularly offshore;
- The results provide data that can contribute towards the certification of a project.
So if you’re interested in guaranteeing structural integrity and achieving a safe and economical pile installation on your project, consider Pile Driving Monitoring from the beginning.