This standard provides guidance for conducting lateral dynamic load tests on piles to determine their load-deflection characteristics. It details the required apparatus, testing procedure, data collection, and methods for analyzing results to assess lateral pile capacity and stiffness.
Guide for lateral dynamic load test on piles
Quick Reference Values
Minimum distance of reference frame from test pile3 times the pile diameter or 1 m, whichever is greater
Least count of dial gauges for displacement0.01 mm
Recommended hammer weight1 to 2 percent of the anticipated safe lateral load
Blow count for seating the pile capAbout 10 blows
Key Formulas
R(t) = F(t) - m * a(t) — Simplified formula for dynamic soil resistance where F(t) is measured force, m is pile mass and a(t) is measured acceleration.
k = P/y — Lateral pile head stiffness, where P is the lateral load and y is the corresponding deflection.
Practical Notes
The results are highly dependent on the quality of instrumentation and the expertise of the personnel performing the test and analysis.
This dynamic method is faster and often more economical than a static lateral load test but requires specialized equipment and interpretation, often involving proprietary wave-equation analysis software.
The analysis provides a load-deflection curve, which is the primary output used by geotechnical and structural engineers for foundation design.