Model Uncertainties in Resistances of Steel Members

In L. Podofillini, B. Sudret, B. Stojadinovic, E. Zio and W. Kröger (eds.), Safety and Reliability of Complex Engineered Systems - Proceedings of the European Safety and Reliability Conference ESREL 2015, Zurich, 7-10 September 2015. Leiden: Balkema/CRC Press, p. 4189-4195, 2015, ISBN 978-1-138-02879-1 (Hbk + CD-ROM), 978-1-315-64841-5 (eBook PDF).It is recognised that structural resistances can be predicted by appropriate modelling of material properties, geometric variables and uncertainties related to a model under consideration. The effects of variability of materials and geometry on reliability of steel structures are relatively well understood. However, better description of model uncertainties is desired as they significantly affect reliability of most steel structures. Improved information on the model uncertainties can be utilised in both structural design and assessment of existing structures. In the latter relative importance of the model uncertainties may increase since tests may reduce the uncertainties in basic variables.
The submitted study provides a general concept of the model uncertainty. Statistical data and available probabilistic models for the uncertainty in resistance of steel members are overviewed. Simple engineering formulas mostly based on the models provided in Eurocode 3 are taken into account. Generally applicable models for the model uncertainties are then proposed. To facilitate practical applications the partial factors for the model uncertainties are derived using a semi-probabilistic approach.
Description of model uncertainties can be a crucial problem in reliability verifications of steel structures. That is why the present study is focused on the model uncertainties in resistance of steel members.