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The following steps will be followed in the compression pile load test:
1. After the curing period, the pile head will be broken to good concrete and the exposed vertical reinforcements will be cut. The pile head will be levelled with good morter.
2. A convenient hydaulic jack will be placed on the levelled head of the pile having two steel plates (of sufficiant thickness, minimum 50 mm) - one at the bottom of the jack and the other at the top of it.
3. A loading platform will be built (of steel girder) of suitable size tying all the anchor piles over the jack keeping some gap in-between. This tying of the anchor piles can be done with the help of the vertical reinforcement of the anchor piles.
4. The load arrangement will be such that when the test pile is under compression the anchor piles will be under tension.
5. Two datumn bars (preferably of steel chennel section of 100 to 150 mm) will be placed at opposite sides of the pile keeping the supports atleast 1.5 m away from the pile.
6. Displacement measuring gauges (4 nos LVDTs) will be placed at the datumn bars and the 4 corners of the bottom plate above the pile.
7. The arrangement for the operation of the hydraulic jack will be placed sufficiantly away from the loading platform, in order to minimise potential hazerd.
8. The pile is loaded suitably and the reading of the LVDTs will be recorded. Generally, the pile is loaded with 20% of the permissible compression load in a single step.
9. Two types of method of loading are there -
a. Continuous incremental load with 20% steps having 15 minutes gap in-between.
b. Stepwise incremental and dectrmental load with 20% steps having 15 minutes gap inbetween. That means the load will go to the required level in steps and then come down to zero in steps. Again the load will go to the next level in steps and then come down to zero in steps. Likewise the load will reach to the final level.
10. If the settlement of single step load increment is more than 0.1 mm within 15 minutes than we have to wait for another 15 minutes and measure settlement. If the settlement is more than 0.2 mm within 30 minutes we have to wait another 30 minutes and record settlement before further increment.
11. After reaching final load 24 hours observation periood is there. During this time settlement is recorded in every 1 hour.
12. After observation period load decrement starts. Load decreases in the same way as it was increased.
13. After removal of the entire load, 6 hours observation period is there. During this period hourly gauge readings are recorded.
14. Then the data obtained is analysed for skin friction and end bearing of the pile.
