Uncertainties in resistance models for sound and corrosion-damaged RC structures according to EN 1992-1-1

Abstract

Resistance of civil engineering structures is primarily dependent on material properties, geometry and uncertainties related to an applied model. While materials and geometry can be relatively well described, the resistance model uncertainty is not yet well understood. The present paper improves the general concept for the model uncertainty from the Probabilistic model code of the Joint Committee on Structural Safety. Influences affecting results obtained by tests and models and effects of actual structural conditions are overviewed. Statistical characteristics of the uncertainties in resistance of reinforced concrete members are then provided considering simple engineering formulas based on EN 1992-1-1 models and effects of deterioration. To facilitate practical applications the partial factors for the model uncertainties are derived using a semi-probabilistic approach. It appears that the model uncertainties are substantial for shear resistances while they are less significant for the well-established models used for bending resistance and axial compression without buckling. Uncertainty in test procedures seems to be less important in common cases. The effect of the resistance uncertainties on structural reliability seems to be more significant for corrosion-damaged structures than for sound structures. Consequently the quantification of the model uncertainties is a key issue when assessing corrosion-damaged reinforced concrete structures. Further research should be focused on model uncertainties related to the models for shear and corrosion-damaged structures considering the fib Model Code 2010.