Reliability-Based Geotechnical Design:
From Theory to Practice

Professor Gordon Fenton

Abstract

Geotechnical design codes are increasingly migrating towards reliability-based design concepts. What this means is that geotechnical designs are starting to be specifically targeted at a failure probability that is societally acceptable and that depends on both the severity of failure consequences and the level of understanding of the site and prediction model. For example, the foundation of a hydro-electric dam, whose failure may result in significant downstream damage and potential life-loss, should be designed to have a lower failure probability than the foundation of a storage shed. In addition, increased site investigation and/or modelling effort should be rewarded by allowing a more cost-efficient geotechnical design, while maintaining the target failure probability to an acceptable level.

In order to properly employ reliability-based design concepts, a basic understanding of the underlying probability concepts, including random field models of the ground, as well as the link between site and model understanding and failure probability, is required. This lecture explores first these fundamental probability concepts and then discusses how they were used to calibrate the most recent edition of the Canadian Highway Bridge Design Code, Section 6: Geotechnical Systems.

About Professor Gordon Fenton

Dr. Fenton is a Professor cross-appointed to the Civil Engineering and Engineering Mathematics Departments at Dalhousie University. His research interests include probabilistic modelling of geotechnical systems and the development of geotechnical reliability-based design codes, and he has authored over 140 peer-reviewed papers. He is currently Chair of the Canadian Highway Bridge Design Code Geotechnical Systems Committee, a member of the Canadian National Building Code Task Group on Climatic Loads, and a member of the Canadian National Building Code Standing Committee on Structural Design. He is also the North American Managing Editor for the international journal “Georisk”, past chair and current member of the ASCE Geo-Institute Risk Assessment and Management Committee, and vice-chair of the ISSMGE Engineering Practice of Risk Assessment and Management Committee. For his research efforts, Dr. Fenton has received the Thomas C. Keefer Award from the Canadian Society for Civil Engineering, the George Stephenson Medal from the Institution of Civil Engineers, UK, the Gzowski Medal from the Engineering Institute of Canada, and was elected a Fellow of the Canadian Academy of Engineering. His research work is summarized in his textbook “Risk Assessment in Geotechnical Engineering”, Wiley (2008).

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