DFI Journal - The Journal of the Deep Foundations Institute
Volume 18, Issue 2, November 2024
DOI: 10.37308/DFIJnl.20240222.307
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Application of the Wave Equation to the Dynamic Capacity of Grouped Piles
Article Type: Research Paper
Johnathan of Blanchard & Richard A. Coffman
Abstract
Two instrumented pile groups, including one group of seven H-Piles (HP 14x102 piles) and one group of seven Pipe Piles (457 mm diameter, closed-ended Pipe Piles) were driven at a site in Northeastern Arkansas. Stress waves in the piles were monitored during pile driving utilizing 350-ohm resistance strain gauges. The recorded stress waves were compared to estimated stress waves from wave equation analyses performed using GRLWEAP (2010). The pile forces for each monitored depth were compared to predicted forces from GRLWEAP (2010), Case Pile Wave Analysis Program (CAPWAP), and Pile Driving Analysis (PDA).
The predicted stress waves were in good agreement with the observed stress waves (regression coefficient values greater than 0.8); however, there was considerable error regarding the prediction of maximum forces, particularly at the pile toe. The pre-construction wave equation predicted forces were within 50 percent (H-Piles) and 30 percent (Pipe Piles), respectively. However, at the pile toe, the errors
Keywords:
driven piles, driving stresses, strain gauges, wave equation, group piles, blow count depth matching