A reliability-based displacement criterion for design of pile foundations (PI: Prof. Zhang LM; Co-I: Prof. Tang WH; Research students: Miss Agnes NG, Mr. Yao XU, Miss CHU, Lai Fan)

Reliability-based design codes such as Eurocode 7, LRFD Bridge Design Specifications, National Building Code of Canada, and Geo-Code 21 of Japan represent the future direction of geotechnical design and are being gradually implemented in many countries to replace the conventional deterministic design approach.  Presently, these codes use reliability principles for designing for the ultimate limit state.  However, the serviceability limit state is still considered using the conventional deterministic approach despite the presence of significant uncertainties. In practice, many geotechnical works such as building foundations are more often governed by serviceability limit requirements rather than the ultimate limit state.  Therefore, a reliability-based displacement criterion is urgently needed to enhance the design for serviceability in these important codes and to cope with construction risk.   

The major part of this research is to develop a reliability-based displacement criterion for geotechnical design that will complement and enhance the deterministic serviceability criterion in such important design codes as Eurocode 7 and AASHTO’s LRFD Specifications.  With the reliability-based displacement criterion established, the design philosophies of these codes for both ultimate limit and serviceability limit states would be fully consistent.  To cater to specific needs for Hong Kong and conditions in Hong Kong, performance data of buildings, large-diameter bored piles and long driven piles from Hong Kong will be used as a basis for this study.