N° 170. 1985. Basic Notes on Model Uncertainties - State-of-the-Art Report Liquid and Gas Tightness of Concrete Structures - Progress Report
In the whole set of uncertainties (statistical et al.) associated with any problem of structural reliability, model uncertainties have a special place. On one hand they cannot be easily assessed and taken into account , on the other hand they cannot be in general considered as negligible.
In the past they have been implicitely covered for a part by the choice of "safe-side models", and for another part by increases of safety elements (partial factors et al.). This covering, was made by poorly coordinated decisions, and it resulted in heterogenous and widely empirical reliability degrees.
For improving, this situation a general and systematic study of this problem has been undertaken within CEB Commission I and is presented herafter as a "Basic Note on Model Uncertainties". This Basic Note was drafted by G. KONIG, D. ROSSER and B. WITTKE. It should be considered as a state-of-the-art report collectinp, the available concepts and models for the treatment of model uncertainties in structural design calculations.
The note takes account of several farmer contributions by Commission members (H. MATHIEU, M. KERSKEN-BRADLEY, L. OSTLUND,
B. LEWICKI) as well as of comments and discussions during the 5th to 8th session of the Commission I. The English wording was checked by H.B. GOULD.
The 3rd draft (September 1984) was finally checked by H. MATHIEU and L. ÖSTLUND and it is naw approved by CEB Commission I for publication.
An Appendix with several practical applications of the models and proposals in the main text was added to the Basic Note for illustration. This Appendix is not covered by the Commission I approval, especially with respect to the numerical values which are dependent on the limit-states under consideration.
