Safety formats for non-linear analysis of concrete structures

For realistic modelling of reinforced concrete structures, non-linear models are often inevitable, which raises the question of an appropriate safety format for non-linear analysis. This paper gives an overview of available safety formats and discusses their advantages and disadvantages. An analysis of available round robin tests and modelling competitions shows that current safety formats do not properly account for the modelling uncertainty of non-linear analysis. Based on this observation a new safety format was proposed which allows one to explicitly account for the modelling uncertainty. To avoid any interaction of the modelled response with the safety format, the mean in situ material parameters should be used in the non-linear analysis and a resistance safety factor is used to assure the intended reliability level. The application of the new safety format to beam sections loaded in bending showed that it offers a reliability level that is in good agreement with the target reliability.