Pile Testing

Static Tests

Pile tests are conducted on single piles or groups of piles to ensure they meet required conditions. For pile groups, caps are used to simulate actual use conditions. Load application and deflection measurements are typically taken at the pile top. This process verifies the structural integrity and load-bearing capacity of the piles, ensuring they perform as expected in real-world conditions.

Vertical Load Test

In this test, a vertical downward load is applied to the pile top using a hydraulic jack against a rolled steel joist or suitable load frame with adequate kentledge or reaction piles. Settlement is recorded using dial gauges or LVDTs.

The load is applied in increments of about 20% of the estimated safe load for all static tests. Settlement criteria should adhere to IS 2911 Part IV (latest revision preferred). This method ensures accurate assessment of the pile’s compression capacity and settlement characteristics under load.

Pullout Load test

In pull-out tests, a hydraulic jack rests on rolled steel joists supported on the ground. The jack reacts against a frame attached to the top of the test pile. When operated, the jack pulls the pile upward, transferring the reaction force to the ground through the supports. This method assesses the pile’s tensile strength and the interaction between the pile and surrounding soil.

Lateral Load Test

In lateral load tests, a hydraulic jack with a gauge is positioned between two piles or pile groups under test. The reaction can be obtained by other suitable means. When conducted with a jack between two piles or groups, the full load imposed by the jack is considered the lateral resistance of each pile or group. Displacement is measured using two dial gauges or LVDTs, ensuring precise readings of the pile’s lateral response under load.

Non-Destructive Testing

Pile Integrity Test

Pile integrity testing evaluates the physical dimensions, continuity, and material consistency of piles. This method is popular due to its simplicity, speed, and cost-effectiveness, allowing quick testing of numerous piles on-site using a low strain method. The test determines the integrity of individual, vertical, or inclined piles by measuring and analyzing the velocity (and optionally, the force) response of the pile induced by an impact device, typically applied axially at the pile head. The standard for this test is ASTM Designation D 5882-96.

High Strain Dynamic Pile Load Test

High Strain Dynamic Load Testing evaluates pile load-bearing capacity and integrity, similar to static load tests. Standardized by ASTM D4945, this method is convenient, reliable, and allows testing of multiple piles per day. Conducted using a Pile Driving Analyzer (PDA) from PDI, USA, it records force and velocity under drop-weight impacts. Field results are analyzed with the Case Pile Wave Analysis Program (CAPWAP) to refine soil parameter assumptions. This technique provides quick and accurate assessments of pile capacity and integrity.

The output from the test result can be summarized as below: