Evaluation of WBUZPILE Design Methodology and the Development of a LRFD Driven Pile Resistance Factor Calibration for Alabama Soils

摘要

In 2007, The American Association of State Highway and Transportation Officials required pile foundations to be designed using the Load Resistance Factored Design (LRFD) method. The Alabama Department of Transportation (ALDOT) utilizes the LRFD method, however the LRFD resistance factor used in ALDOT design is un-calibrated, and is not necessarily representative of Alabama soils. Additionally, the ALDOT pile design program (WBUZPILE) has not been verified as a reliable program for design. In this study, it was found that WBUZPILE tends to over-predict the ultimate capacity of concrete piles, and is more suitable for predicting the capacity of steel H-piles when compared to static load test data. A comparison was performed with the design program DRIVEN, and yielded similar results. A statistical analysis was performed on the results of WBUZPILE, and resistance factors were calibrated using Paikowsky's method. The calibration results show lower values when compared to the currently used resistance factor. A dynamic analysis was also performed in this study to quantify pile setup in the state of Alabama. The results show a greater increase in capacity between End of Drive (EOD) and Static Load Testing, when compared to the average capacity increase between EOD and Beginning of Re-strike. The greatest amount of pile setup was observed for piles driven in clay.