S - Kam Ng PhD Dissertation Final.pdf - Digital Repository of CCEE ...

4check pile integrity; (5) evaluate driving system performance; (6) assess soil resistancedistribution; and (7) less expensive than static load test. For these reasons, dynamic analysismethods are used to evaluate pile performances and assess surrounding soil behaviors duringand after pile driving in this research. The following methods were chosen: wave equationanalysis using the Wave Equation Analysis Program (WEAP), pile driving analysis using thePile Driving Analyzer (PDA) method, and pile resistance and dynamic soil propertiesestimations using the CAse Pile Wave Analysis Program (CAPWAP).WEAP was developed based on Smith’s (1962) numerical mathematical model thatexploits the one-dimensional wave propagation concept to characterize the hammer-pile-soilsystem under a hammer impact. Subsequently, WEAP was further developed to incorporateall available hammers information by Goble, Rausche and Likins (GRL) into a commercialprogram, GRLWEAP. To accurately capture the hammer impact on a pile, Pile DynamicInc. (PDI) developed a data acquisition equipment known as PDA in the 1960s to measurestrains and accelerations near the pile head during driving. PDA converts the measuredstrains and accelerations to forces and velocities respectively and uses them to estimate thepile resistance—this approach is known as Case method. Utilizing the PDA records, theCase method and the wave equation method, they developed an improved pile analysismethod known as CAPWAP in the 1970s. CAPWAP uses the Smith’s model and refines theCase method results by performing force and velocity signals matching process. Despitehaving numerous advantages over other methods, the aforementioned dynamic analysismethods have some challenges, such as finding suitable dynamic soil parameters, requiringunderstanding of wave mechanics and requiring operational as well as interpretational skills.The details of the dynamic analysis methods are described in Chapter 2 of the dissertation:Literature Review.1.2. Current State of Knowledge1.2.1. Soil propertiesStandard Penetration Test (SPT) is the most commonly used in-situ soil tests in Iowa