1. ISSMGE Joint TC205/TC304 Working Group “Discussion of statistical/reliability methods for Eurocodes” Chapter 9 Robustness in geotechnical design Brian Simpson (convenor), Hongwei Huang, Charnghsein Juang, Sónia H. Marques, Bernd Schuppener, Timo Schweckendiek, Paul Vardanega, Norbert Vogt

2. Chapter 9 – Robustness in geotechnical design Definitions of Robustness
Ability to accommodate events and actions that were not foreseen or consciously included in design.
The sensitivity of the final design to variations of the known parameters within their anticipated range of uncertainty.
The robustness, or accuracy, of particular calculation models, in terms of their ability to represent the real situation reliably.
Resilience – the ability of a structure to be recovered after it has failed. Th

3. Accommodating events and actions that were not foreseen in design
Chapter 9 – Robustness in geotechnical design The chapter has two parts
Part A
Accommodating events and actions that were not foreseen in design
Part B
Accommodating variations of the known parameters within their anticipated range of uncertainty

4. Chapter 9 – Robustness in geotechnical design Conclusions of Part A
Accommodating events and actions that were not foreseen in design
For unforeseen events, the effect should not be disproportionate to the cause.
“Prescriptive measures” are important.
Required margins of safety relate more to the magnitudes of the lead variables – strength, loads, etc – than to their uncertainties.
So partial factor methods might be more appropriate than (simple) consideration of b.
For large project, multi-disciplinary reviews, including reliability analysis, can be important.

5. Chapter 9 – Robustness in geotechnical design Conclusions of Part B
Accommodating variations of the known parameters within their anticipated range of uncertainty
Propose a process of “Robust geotechnical Design”.
Effectively accounts for the effect of the variation in “noise factors” while simultaneously considering the safety and cost efficiency.
Describes how the robust design is optimised (knee point of the Pareto front approach), illustrated with case studies.

6. Chapter 9 – Robustness in geotechnical design Conclusions of Part B
Accommodating variations of the known parameters within their anticipated range of uncertainty
Propose a process of “Robust geotechnical Design”.
Effectively accounts for the effect of the variation in “noise factors” while simultaneously considering the safety and cost efficiency.
Describes how the robust design is optimised (knee point of the Pareto front approach), illustrated with case studies.

7. ISSMGE Joint TC205/TC304 Working Group “Discussion of statistical/reliability methods for Eurocodes” Chapter 9 Robustness in geotechnical design Brian Simpson (convenor), Hongwei Huang, Charnghsein Juang, Sónia H. Marques, Bernd Schuppener, Timo Schweckendiek, Paul Vardanega, Norbert Vogt
Lots to think about!