High Strain Dynamic Pile Testing (HSDPT)

HSDPT or High Strain Dynamic Pile Testing is an important test besides load test done on piles which had been piled into the ground to ensure that the piles installed are actualy drived to set and there are no major settlement once the pilecap has been casted on it. HSDPT is a simple test yet very effective that even the slightest pile cracks or settlement could be indicated. The major indications to be checked during this test are the values of RMX (max pile capacity), TSX (max tension stress), EMX (energy transfered to pile), VMX (max velocity at tranducers), CSX (max axial compression stress), DFN (displacement), BTA (pile integrity), SFT (shaft friction total) and CSB (computed pile bearing capacity).
In order to get a good quality data, the hammer has a reasonable centrallized impact to minimize bending effects and make sure all tranducers are operational and properly connected to the pile. Items to check before the commencement of the test are:

1) All F and V curves should be zero before impact.

2) The velocities at the end of the record return to zero value (pile at rest).

3) The force reponces at any time do not vary by more than 0.33 to 0.5 of the maximum force value. Variation generally indicates bending usually shortly after impact. If this occur, then realignment of the hammer or additional cushion is required to minimize bending.

4) The force at the end of the test return to zero value. Non-zero values generally indicates that the effect of the impact is still generating stresses to the pile.

5) The signals should be free of high frequency noices to avoid errors.