Assessment of Vibratory Hammer installation via GRLWEAP and via Dynamic Measurements collected with the PDA-PPT Presentation

PPT Presentation

Pdf Summary

The presentation examines whether PDA instrumentation and GRLWEAP software—traditionally used for impact-driven piles—can support vibratory pile installation. Vibratory hammers generate oscillating forces whose magnitude depends on eccentric moment and frequency. Unlike impact driving, vibratory driving generally produces lower pile stresses, and penetration speed does not reliably indicate bearing capacity. Consequently, conventional bearing graphs are of limited value for vibratory work.<br /><br />PDA measurements of strain and acceleration can provide frequency, force and stress estimates, and acceleration. PDI-VIB processes the signals to estimate additional quantities, including velocity, displacement, power, and soil resistance during driving. Because the PDA is a dynamic instrument, it does not measure static crowd or line force; these must be assessed separately. Displacement estimates also require adjustment, with average penetration speed measured independently.<br /><br />A 2019 case study monitored steel piles at two sites using a Movax Sonic SideGrip hammer. Piles were driven in side-grip and top-grip phases, with instrumentation at two elevations. Measurements captured pile response and helped identify features such as out-of-phase strains. A subsequent GRLWEAP drivability analysis demonstrated how hammer and soil inputs can be used to estimate performance, but results depend on appropriate, manually selected soil parameters.<br /><br />The presentation concludes that GRLWEAP can provide useful drivability estimates, though local experience is important and bearing graphs are not especially helpful. PDA and PDI-VIB measurements can help assess hammer performance, pile stresses, and installation resistance. Continued field data collection is recommended to improve understanding of hammer behavior and soil response, refine analyses, support project bids and feasibility studies, and improve cost estimates.

Keywords

PDA instrumentation

GRLWEAP

vibratory pile driving

pile drivability

vibratory hammer

pile stresses

soil resistance

PDI-VIB

penetration speed

dynamic pile analysis