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

xviABSTRACTBecause of the mandate imposed by the Federal Highway Administration (FHWA) onthe implementation of Load Resistance Factor Design (LRFD) in all new bridge projectsinitiated after October 1, 2007, research on developing the LRFD recommendations for pilefoundations that reflect local soil conditions and construction experiences for the State ofIowa becomes essential. This research focuses on the most commonly used steel H-pilefoundation. The research scope is to (1) characterize soil-pile responses under pile drivingimpact loads, and (2) understand how the generated information could be used to improvedesign and construction control of piles subjected to vertical loads in accordance with LRFD.It has been understood that efficiency of the pile foundation can be elevated, if theincrease in pile resistance as a function of time (i.e., pile setup) can be quantified andincorporated into the LRFD. Because the current pile foundation practice involves differentmethods in designing and verifying pile performances, the resulting discrepancy of pileperformances often causes an adjustment in pile specifications that incurs incrementalconstruction costs, significant construction delays, and other associated scheduling issues.Although this research focuses on the most advanced dynamic analysis methods, such as PileDriving Analyzer (PDA), Wave Equation Analysis Program (WEAP), and CAse Pile WaveAnalysis Program (CAPWAP), the accuracy of these methods in estimating and verifyingpile performances is highly dependent upon the input selection of dynamic soil parametersthat have not been successfully quantified in terms of measured soil properties.To overcome these problems and due to the limited data available from the Iowahistorical database (PILOT), ten full-scaled field tests on the steel H-piles (HP 250 × 63)were conducted in Iowa. Detailed in-situ soil investigations using the Standard PenetrationTest (SPT) and the Cone Penetration Test (CPT) were completed near test piles. Push-inpressure cells were installed to measure total lateral earth and pore water pressures during thelife stages of the test piles. Soil characterization and consolidation tests were performed.Pile responses during driving, at the end of driving (EOD), and at restrikes were monitored