Dynamic Load Testing (DLT) is a frequently used worldwide technique to evaluate the bearing capacity of piles. The Profound PDA/DLT-system is used for both DLT and for Pile Driving Analysis (PDA) as a powerful tool to control the pile driving process and reduce risks involved.
Dynamic Load Testing
The Dynamic Load Test (DLT) is a considerably faster and cost-effective alternative for a Static Load Test (SLT). This is in particular related to Eurocode 7 whereby current pile design safety values are valid till 2017, then either a reduction will be implemented or piles need to have been load-tested. Dynamic load tests can be part of the calculation of safety coefficients for a specific type of pile or installation method, if the DLT tests are calibrated by one static load test in a comparable situation as reference. The DLT tests can be done very time efficiently and at a much lower costs than SLT. With the Profound PDA/DLT-system the bearing capacity of several piles can be assessed in a single day. DLT is used for cast-in-place, prefabricated concrete piles and all types of steel piles.
The load is applied by an impact hammer or a suitable drop weight onto the prepared pile head. The generated compression wave travels down the pile and reflects upwards. This reflected wave contains information about the shaft friction, toe resistance and possible pile defects. The measured signals are processed and automatically stored by the PDA/DLT-system. The data can easily be retrieved for further review, graphical presentations or reporting in full accordance with ASTM D4945-12.
Pile Driving Analysis
During pile driving the performance of the hammer, the condition of the cushion, the behaviour of the pile and the driving resistance of the soil are accurately monitored and analysed.
The additional knowledge obtained by performed PDA can pay for itself many times over by:
- Reducing the risk of damage to the pile or hammer.
- Reducing the risk of damage to the superstructure caused by failure of the foundation.
- Optimisation of the final depth of driving, which may result in a shorter pile length.
- Facilitating the prediction of pile driving and selection of the correct hammer for future projects. A quality record of each pile can be supplied to clients and authorities.