Step by step guidance for pile load test

The load test of pile is carried on to find out the load bearing strength of a pile. The test provides the following value :-

a. Ultimate load value
b. Safe load value
c. Settlement under several values of loads

The following methods are used for load test :-

The set-up comprises of two anchor piles which are arranged with an anchor girder or reaction girder at their top.

The test pile is set up among the anchor piles as like foundation pile is set up. There should be minimum 3B or 2.5m clearance between test pile and anchor pile.

The test is conducted after a rest period of 3 days once the set up in sandy soils is completed as well as after one month period in slits and soft clays.

The load is provided via a hydraulic jack that is supported on the reaction girder or truss. The calculation for pile movement is done with regard to a fixed reference mark.

The load is employed in equivalent increment of approx 20% of the permissible load.

3 digital gauges are used to record the settlement.

Each phase of the loading is sustained unless the rate of movement of the pile top does not exceed 0.1 mm per hour in sandy soils and 0.02 mm per hour for clayey soils as maximum of two hours.

As each load is raised, settlements are ascertained as 0.5, 1, 2, 4, 8, 12, 16, 20, 60 minutes.

The loading should be maintained up to twice the safe load or the load at which the total settlement attains a certain value.

The load is eliminated in the equivalent decrements at 1 hour interval & the final rebound recorded 24 hours once the total load is eliminated.

Plot a graph of load settlement and create a curve for loading along with unloading procured from a pile load test.