DFI Journal - The Journal of the Deep Foundations Institute
Volume 3, Issue 2, November 2009
DOI: 10.1179/dfi.2009.009
All Journal papers are free to DFI members.
If you are a member, please click on the "Login" link at the top of this page to to download this paper.
Not a member? Join here to get access to all papers or click the purchase button below to access this paper only.
Uncertainty and Bias in Evaluation of LRFD Ultimate Limit State for Axially Loaded Driven Piles
Article Type: Research Paper
Schneider, J.
Abstract
Selection of resistance factors within Load and Resistance Factor Design (LRFD) requires accurate assessment of uncertainty and bias in load and resistance. To date, many studies have focused predominantly on the assessment of uncertainty, while the potential for bias appears to be the dominant factor in design for consistent levels of reliability under a variety of situations. Bias comes from factors which have been ignored in design method development but significantly influence resistance when extrapolating from conditions typical of databases to those at a given site. Uncertainty and bias can be quantified as the coefficient of variation and mean (or median) of a data set, respectively, for statistical assessment of load and resistance factors. This paper first presents an overview of statistical assessment of resistance factors, and then discusses factors that influence uncertainty and bias when extrapolating to situations outside of conventional databases of driven pile axial capacity.
Keywords:
driven piles, ultimate capacity, LRFD, reliability