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

217Bridge Design Specifications have been developed for general soil conditions and pile types.These AASHTO Specifications cannot reflect the local soil conditions, design methods, andconstruction practices, which may result in conservative foundation designs. Even thoughAASHTO allows the use of regionally-calibrated resistance factors in LRFD pile designs,regional usable pile data, such as pile driving data with PDA records, is insufficient fordeveloping the resistance factors. In recognizing these problems, extensive soil investigationsand 10 field pile tests described in Chapter 3 and Ng et al. (2011) were conducted to populatethe existing historical PIle LOad Tests (PILOT) database, which has been electronicallycompiled by Roling et al. (2010). Given that a recent survey of more than 30 StateDepartments of Transportation (DOTs) conducted by AbdelSalam et al. (2010) revealed thatsteel H-pile is the most common foundation type used for bridges in the United States, theresearch studies focus on the most commonly used steel H-pile foundations. Using thePILOT database and the recently completed pile test results, the regionally-calibrated LRFDresistance factors are computed specifically for the construction control methods, WaveEquation Analysis Program (WEAP) and CAse Pile Wave Analysis Program (CAPWAP),using the First Order Second Moment (FOSM) method suggested by Barker et al. (1991).Since piles are typically designed using static analysis methods and theirperformances are verified using the construction control methods during construction, it hasbeen a challenge to attain the design pile resistance during construction. As a result of thediscrepancy, pile driving specifications are normally adjusted accordingly, such as increasingpile length. This adjustment may increase construction costs, delay construction schedule,and cause contractual challenges. To enhance the design and construction efficiencies ofpiles, a methodology was developed by the writers to minimize the discrepancy between thedesign and field pile resistances by integrating the WEAP and CAPWAP as part of thedesign process.Although the incorporation of pile setup into pile designs improves the efficiency ofbridge foundations, it has not been accounted for in the latest AASHTO (2010) LRFDSpecifications. Using the pile setup quantification method developed in Chapters 3 and 4