Post-test grouting is an important aspect in proposing bi-directional load test for test pile. As more often than not, the test is proposed on working piles which requires grout back to enable proper load transfer throughout the entire pile length. Preliminary pile that requires post-test grouting is usually due to the requirement of subsequent high strain dynamic test.
Therefore the working pile’s condition in its serviceability limit state should not in any way affected by the test. Bi-directional test pile, regardless of how small the gap, if left ungrout or grouted improperly is essentially a structural defect that could be detrimental to the pile’s performance and durability in the long term.
There are two identical voids found in specific places in the pile after bi-directional testing:
1.) bi-directional hydraulic jacks which is filled with water after the test,
2.) annulus gap inside pile near to the bottom of the jack (jack opening).
It is important to note that the annulus gap in the pile should be a uniform horizontal crack-through in that plane through the top and bottom steel bearing plates that has the jacks welded together. Uneven or non-uniform crack-through potentially left the pile impossible to grout back, especially so in big diameter pile.
To make the post-test grouting successful, each jack needs to have two lines of hydraulic hoses (inlet/outlet) to enable the expulsion of water and/or air for grout to fill in. The same goes for the annulus gap of the pile through separately installed grouting pipes.
At Bi Directional Test Consult, we take stride in ensuring the post-test grouting for each and every working test pile is successful with high performance grouting material that’s flowable, has extended pot life and can achieve equal or greater strength than the designed concrete compressive strength, so that the working pile’s long term durability and performance will not be adversely affected. Numerous working piles grouted back by us have shown 100% Integrity value (BETA) in subsequent high strain dynamic test.