The construction of foundation for high-rise buildings and infra-structure buildings such as roads, flyover, tunneling road, boiler, and many other structural buildings need a good control to its construction quality; thus needs a comprehensive testing system which can gives the actual condition for other production piles. One of the most popular foundation systems is the Pile Driving Analyzer (PDA) test which is a nice and simple non-destructive method to predict pile capacity, settlement and load transfer.
Pile testing with Pile Driving Analyzer – PAX model (latest version by PDI Inc. – USA)1 will carry out on concrete driven pile with prepared by to produce some output at the time when pile dynamically loaded such as:
1. Pile axial resistance
2. Pile settlement
3. Pile integrity
4. Energy and load transfer
Many PDA output from one pile testing performs as a big benefit compare to static load test using dead weight; this benefits for example are time schedule, soil behavior, and cost.
Pile axial capacity acquire from wave reflection traveling along the pile and the exist of soil resistance through the side of pile plus the end-bearing resistance at the pile bottom and then recorded with a pair of strain transducer and accelerometer position approximately 1.5 x diameter from pile top.Pile integrity and uniformity is one of PDA output.. All of this problems are common happen to bore pile construction; with the acceleration curve got from PDA test, the location of these anomaly can detected and predicted.Good correlation between dynamic and static test resistance have been admitted; this was proven with the presence of ASTM D-4945-962 as the standard of pile dynamic testing.
PDA TEST EQUIPMENT
1. PDA – PAX
2. (2) Strain transducer to measure the strain occur in test pile
3. (2) Accelerometer to measure the acceleration occur in the test pile
4. Connection cable or wireless box
5. Miscellaneous tools for installing the instrument to test pile.
METHOD OF WORK
The top of test pile shall be in flat and good condition without soft concrete. At two side of test pile with approximately 1.5 Diameter (D) distance from pile head, a pair of strain transducer and accelerometer attached and connected through the connection cable or wireless with bluetooth connection to the PDA-PAX. Testing execute by making an impact to the pile top using a proper hammer which is correlate to 2% of ultimate design of pile capacity. This impact was expected not to harm the pile; thus the stress at pile head shall not over than pile compression strength so the pile shall not break at testing time. This can be controlled by testing engineer by showing the stress occurs on the pile head.
PDA TEST ADVANTAGE.
1. Testing time range about 1-2 hour per test pile.
2. Lower cost compare to static load test
3. Pile behavior can achieve by perform CAPWAP analysis.
4. PDA can be done at location where static load test almost impossible to do such as offshore and inside the building.