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

xviiusing PDA. PDA records were used in CAPWAP analysis to estimate the pile performances.In addition, hammer blow counts were recorded for WEAP analysis. After completing allrestrikes, static load tests were performed to measure the pile resistance.The information collected from the tests provided both qualitative and quantitativestudies of pile setup. Unlike the empirical pile setup methods found in the literature,analytical semi-empirical equations are developed in terms of soil coefficient ofconsolidation, SPT N-value, and pile radius to systematically quantify the pile setup. Theseproposed equations do not require the performance of pile restrikes or load tests; both aretime consuming and expensive. The successful validation of these proposed equationsprovides confidence and accuracy in estimating setup for steel H-piles embedded in cohesivesoils. For the similar study on large displacement piles, the results indicate that the proposedmethods provide a better pile setup prediction for smaller diameter piles.Based on statistical evaluations performed on the available database, field tests, andsources found in the literature, it was determined that different uncertainties were associatedwith the estimations of the initial pile resistance at the EOD and pile setup resistance. Toaccount for this difference, a procedure for incorporating the pile setup in LRFD wasestablished by expanding the First Order Second Moment (FOSM) method, whilemaintaining the same target reliability level. The outcome of the research provides amethodology to determine resistance factors for both EOD and setup resistances based onany regional database. Therefore, the practical implementation of pile setup can now beincluded in a pile design, which has not been provided in the latest American Association ofState Highway and Transportation Officials (AASHTO) Bridge Design Specifications.Combining the PILOT database with the field test results, regionally calibratedresistance factors for bridge deep foundations embedded in clay, sand, and mixed soilprofiles were established for the dynamic analysis methods. This regional calibrationgenerated higher resistance factors and improved the efficiency of pile performances whencompared with those recommended by the latest AASHTO Bridge Design Specifications.