STS provides the following testing facilities pertaining to pile foundations
Pile Integrity Tests
Low-strain pile integrity testing is done to give information about the physical dimensions, continuity and consistency of materials used in piles. This test method covers the procedure for determining the integrity of individual vertical or inclined piles by measuring and analyzing the velocity response of the pile induced by an impact device applied axially to the pile normally at the pile head.
The Pile Integrity Tester (P.I.T.) uses the small hand held hammer to generate a low strain shock wave in the pile; the sensitive accelerometer temporarily attached to the pile top then measures the response from the pile bottom or hidden defects along the shaft.
The sensitive accelerometer shall be fixed on a clean pile top area using a suitable bonding material (that is, wax, Vaseline, etc.) in such a way to prevent slippage of the sensor under hammer impacts. It is to be noted that the transducer axis of sensitivity shall be aligned with the pile axis in order to measure correctly the axial pile motion.
The motion sensor (i.e. the accelerometer) shall be placed in general near the centre of the pile. The low strain impact shall be applied to the pile head within a distance of 300 mm from the motion sensor.
Pile Load Tests
Pile load tests are done by using the Kentledge system. One hydraulic jack is placed between the pile head and the primary girder. Four dial gauges are setup to record the settlement of the pile during loading and the release of the load. An average of the four readings is taken for each operation. On the basis of net settlement, pile capacities are verified from the pile load tests.
High Strain Dynamic Tests
High strain dynamic tests are the state of the art pile testing method used in quality assurance for bored piles and driven piles. These tests are effective and save up a lot of time as compared to static load tests. Through these tests force and velocity response of the pile is measured. The response of pile is generated by dropping a hammer on the surface of the pile.