Reliability and Limitations of Dynamic Methods for Predicting Capacity andSettlement of Driven Piles

摘要

Dynamic testing of driven piles is being increasingly used as a means of capacityprediction in the state of Florida. PDA (Pile Driving Analyzer) and CAPWAP (CAse Pile Wave Analysis Program) are dynamic methods extensively used in Florida by the Florida Department of Transportation and its consultants. PDA monitors stresses in the pile during driving by analyzing the force and velocity waves generated by individual hammer blows. CAPWAP is an analysis usually performed some time after driving for selected hammer blows using the force and velocity data measured and recorded by the PDA. CAPWAP is an iterative procedure that uses the velocity data as an input and adjusts the capacity, damping and quake variables until calculated force values are equivalent to those measured. The quality of the match is determined by a defined criteria. CAPWAP is often used to confirm the results of PDA tests. The FDOT has funded research at the University of Florida for the development and maintenance of a dynamic testing database to be used as an archive for pile records and as a means of comparing capacity predictions. Of interest are the values of the input variables used in the analyses and the precision of the two methods.