Action 4.2.1 : Increasing the reliability of degradation curves for engineering uses

Technical Issue

The sensitivity of the site response analysis to ground non-linearities is well known. Characterization of the non-linear behaviour of the ground is mainly based on laboratory tests, that raises the usual questions of representativeness and uncertainties associated with these tests.

Proposed Approach

1. bibliographic synthesis of the published G-g and D-g expressions proposed by various authors
2. potentially implement some specific lab tests
3. characterization of the variability of the curves for a given material
4. representativeness of the lab tests; adjustment on in-situ tests and on actual records in bore-hole and free field
5. relevance of degradation curves expressed as a function of a shear strain ratio g/gr

Deliverable

Bibliographic synthesis and guideline for the choice of the good Ggamma curve in engineering studies.