1. Imprecise Probabilistic and Interval Approaches Applied to
GEORISK2017 Geotechnical Risk from Theory to Practice
&
ISGSR2017 Geotechnical Safety and Risk
Grand Hyatt Denver
Denver, Colorado, United States of America
4-7 June 2017
Imprecise Probabilistic and Interval Approaches
Applied to
Partial Factor Design
Discussion
International Society for Soil Mechanics and Geotechnical Engineering REPORT
Sónia H. MARQUES & Kerstin LESNY

2. en 1997, adopted as eurocode 7, is intended to be applied to the
Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Introduction
en 1997, adopted as eurocode 7, is intended to be applied to the
geotechnical aspects of the design of civil engineering works
the limit state design concept adopted by eurocode 7
is used in conjunction with a partial factor methodology
the selection of appropriate partial factors is important to ensure
the reliability of geotechnical design to eurocode 7
as design values are determined
by applying partial factors to characteristic values
to achieve the required target reliability
eurocode 7 does not provide
any variation in the partial factors
but rather requires that
greater attention is given to other
accompanying measures related to design
supervision and inspection differentiation
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

3. Robustness in the Context of Eurocode 7 Partial Factor Design
Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Robustness in the Context of Eurocode 7 Partial Factor Design
a modern concept of robustness expresses
the degree of independence
among any changes in the whole set of parameters
and the fluctuation of the response
considered
a global specification on a minimum variance
with respect to input variations
the state of play on the assessment of
geotechnical robustness
has been recently extended to
partial factor design
how to measure the performance of a
partial factor format?
how to achieve the required
target reliability ?
which factors are able to maintain
a more uniform reliability level
over a range of design parameters?
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

4. Robustness in the Context of Eurocode 7 Partial Factor Design
Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Robustness in the Context of Eurocode 7 Partial Factor Design
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

5. Robustness in the Context of Eurocode 7 Partial Factor Design
Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Robustness in the Context of Eurocode 7 Partial Factor Design
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

6. Robustness in the Context of Eurocode 7 Partial Factor Design
Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Robustness in the Context of Eurocode 7 Partial Factor Design
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

7. the geotechnical engineer must be able to deal with reliability
Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Imprecise Probabilistic Approaches Applied to the Eurocode 7 Partial Factor Design
the geotechnical engineer
must be able to deal with reliability
in order to provide new insights in
professional practice
this transition has been notedly
characterised by
a natural resistance in the application of
probabilistic approaches
imprecise probabilistic approaches emerge
as a basis for decision-making by the
identification of probability bounds
for scenarios of interest
imprecise probabilistic approaches
are robust whenever insensitive to
small deviations from the assumed
probabilistic models
imprecise probabilistic approaches
have some advantages over precise
probabilism on the capacity to
represent generalised judgement
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

8. Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Imprecise Probabilistic Approaches Applied to the Eurocode 7 Partial Factor Design
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

9. Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Imprecise Probabilistic Approaches Applied to the Eurocode 7 Partial Factor Design
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

10. Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Imprecise Probabilistic Approaches Applied to the Eurocode 7 Partial Factor Design
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

11. Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Imprecise Probabilistic Approaches Applied to the Eurocode 7 Partial Factor Design
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

12. Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Imprecise Probabilistic Approaches Applied to the Eurocode 7 Partial Factor Design
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

13. whenever no information apart from bounds is available
Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Imprecise Interval Approaches Applied to the Eurocode 7 Partial Factor Design
whenever no information apart from bounds is available
intervals may be considered in the form of a model noted that
they are among the most widely used tools to describe
uncertainty by using nonprobabilistic approaches
in the multivariate case
the considered probability level
prescribes a credible region
in the hyperspace
different bounding measures may be applied in order to find
the limit state lower and upper bounds in different scenarios
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017

14. safety margins are applied in order to cope with
Imprecise Probabilistic and Interval Approaches Applied to Partial Factor Design
Conclusion
safety margins are applied in order to cope with
uncertainty and do not necessarily
lead to safety
safety factors are used to avoid
failure in a variety of practices
one motivation for adopting imprecise probabilistic approaches consists on the safety evaluation in the scope of the shear strenght
parametric change by weathering,
example probabilistic interpretation of pillar mining capacity
one motivation for adopting imprecise interval approaches consists on the
safety-based decision discussed on the basis of distinct levels of credibility
considered the limit state lower and upper bounds in different scenarios
eurocode 7 development?
characteristic values
multiple safety factors regarding parametric variability on space and time
Sónia H. Marques
GEORISK2017 & ISGSR2017
4-7 June 2017