National and international code based deterministic and full probabilistic modelling to describe reliability of various Australasian marine structures

The Duracrete carbonation and chloride models (Duracrete, 1998) were first published as a model code in fib Bulletin 34 and have now come firmly into the public domain with the same models publication in ISO 16204 and fib Model Code 2010. These models are complex and have a raft of inputs that although reasonably well defined in fib 34 there are still many details of using these models that are not commonly understood. Concrete associations, notably the International Structural Concrete Association (fib) and Concrete Institute of Australia (CIA) are endeavoring to resolve this by publishing guidance notes but this has proven a difficult task. This paper provides some background on how the fib 34 chloride and carbonation models can be used in full probabilistic and deterministic modes. Although deterministic analyses are commonly undertaken with ‘conservative’ input values the actual reliability of the outcomes is not known. This knowledge is only available if full probabilistic models are transferred to semi-probabilistic models (partial safety factor models, PSF-models). PSF-models can be utilized in a deterministic mode. The paper outlines some difficulties associated with full probabilistic on the one hand and deterministic modelling on the other and gives information on the input variables. It also provides analysis on various structures as examples of their application.