Mulugeta Abay Kebede
Published: 2010
Total Pages: 270
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"Over the past two decades the load resistance factor design (LRFD) has been accepted by the American Association for Transportation and Highway Officials (AASHTO) for the design of bridges. This approach is now gaining widespread popularity in the United States for substructure bridge design, including the design of driven pile foundations, as the states calibrate the geotechnical resistance factors for local geological conditions and practices. This study presents the geotechnical resistance factors calibrated for axially driven pile using the first-order reliability method (FORM) for the target reliability index of 2.33 and 3.0 based on 64 end-of-drives (EOD) and 22 beginning-of restrike (BOR) pile driving analyzer (PDA) test data from nine bridge sites in Missouri. Three static pile capacity prediction methods were used, i.e. the Nordlund, Meyerhof and Beta methods. The work investigated the efficiency of each method based on the bias factor, the ratio of the measured to the predicted capacity of the pile, ([lambda] = R[subscript m]/R[subscript p]), the coefficient of variation (COV), and efficiency factor or the ratio of the resistance factor to the bias factor, ([phi]/[lambda]). It verified that the Beta and Nordlund methods provide better predictions than the Meyerhof method. In addition, a comparison of the resistance factor in current AASHTO LRFD with the calibrated resistance factor shows that validating the resistance factors in the AASHTO may result in less reliable design. Finally, the recommended resistance factors for LRFD design are provided for use in Missouri. In addition, further refinement of the developed resistance factors is recommended to improve the resistance factors using large quantity and high quality of data that cover wide areas the glaciated plain and southeast lowland geological regions"--Abstract, leaf iii.