Review of Reliability Levels Achieved by Geotechnical Design Codes

Gennaro Esposito, Gordon A. Fenton

In the proceedings of: GeoEdmonton 2018: 71st Canadian Geotechnical Conference; 13th joint with IAH-CNC

Session: Reliability Analysis for Geotechnical Design

ABSTRACT: This paper compares the overall true reliability levels achieved by a variety of design codes from around the world for the Ultimate Limit State of geotechnical systems. We compare the Canadian CHBDC code with the European EN 1997, the American AASHTO, and the Australian AS 4678 and AS 2159. All the codes in this study are reliability-based design codes and their use should produce designs characterized by very similar reliability levels. We use deep foundations and shallow foundations and consider the bias of the design methodology and the variability of true and predicted geotechnical resistance. In general, North-American codes target a lower reliability target than EN 1997 and Australian codes. The study revealed that, despite differences in format, choice of the characteristic values and material factors, all the codes achieve an acceptable overall reliability level for the geotechnical systems considered, with the exception of the EN 1997 for the design of deep foundations. We postulate that the observed consistency is due to implicit inclusion of many sources of uncertainty in the code calibration. Finally, the North-American codes are found to be the most robust due to the higher likelihood of achieving their target reliability level. The European and Australian codes are less robust, as they have a lower likelihood to meet a higher target reliability level.

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Cite this article:
Gennaro Esposito; Gordon A. Fenton (2018) Review of Reliability Levels Achieved by Geotechnical Design Codes in GEO2018. Ottawa, Ontario: Canadian Geotechnical Society.

@article{geo2018Paper416,author = Gennaro Esposito; Gordon A. Fenton,title = Review of Reliability Levels Achieved by Geotechnical Design Codes ,year = 2018}