Dynamic and Static Testing in Soil Exhibiting Set‐Up

Pile foundation studies were conducted on four types of steel piles driven through estuarine deposited soils and into a highly variable glacial deposit to total depths of 33–48 m (110–156 ft). Twenty piles were subjected to dynamic monitoring during initial driving and restriking. For all the monitored piles, static loading tests were carried out to failure and the results compared to ultimate resistances determined in a CAPWAP analysis. With two exceptions, the driving was generally very easy above a depth of 46 m (150 ft). Restriking at different times after driving showed that the penetration resistance increased due to the development of soil set‐up occurring within the first week after initial driving and that the final pile capacities vary considerably and randomly across the site. The CAPWAP‐determined pile capacities at restriking agreed well with the results of the static loading tests (when the latter could be clearly defined and the hammer had been able to move the pile in the restriking). When the capacity could not be defined in the static test, the CAPWAP determined ultimate resistance was as usable as the conventional methods for determining the load limit of the static test.